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Self-made millionaire and serial entrepreneur Scott Galloway says there are two critical secrets to success: Following your passion is "bulls---," and pick a good life partner.

Coca-Cola, the parent company of popular soft drink Coke, has proven enduringly successful over the years: It ranked No. 6 on Forbes' list of the world's most valuable brands in 2018, with a whopping $57.3 billion value.

The company has gotten its share of celebrity endorsements, too: Warren Buffett says he's a "Coke loyalist," and Berkshire Hathaway is a longstanding investor.

If you invested in the company 10 years ago, that decision could have paid off. According to CNBC calculations, a $1,000 investment in Coca-Cola in 2009 would be worth more than $2,800 as of Feb. 15, 2019.

While the company's stock price has been largely steady over the past decade, though, any individual stock can over- or underperform, and past returns do not predict future results.

CNBC: Coca-Cola stock as of Feb. 15, 2019

Shares fell Thursday and were on track for their worst day since the Great Recession. The company's stock price fell 7.5 percent and its net sales fell 6 percent. (Net sales still topped expectations.)

Chief executive officer James Quincey told analysts that currency fluctuations, Federal Reserve interest rate hikes and changing tax rates could be responsible for the stock's slide. "Clearly, that is leading to an [earnings per share] growth that is not what we aspire to," he said.

He expressed similar concerns at the 49th World Economic Forum in Davos: "I think we are in the phase of 2019 where we are likely to see a little less growth. It is going to be a slightly tougher year in macroeconomic terms and we need to work our way through it."

Some analysts see problems facing the traditional soda market overall. Ivan Feinseth, of financial firm Tigress Financial Partners, said on CNBC's "Squawk Box," that "there is no growth in carbonated soda," and that brands like Coke and longtime rival Pepsi need to get creative.

They'll need to "continue to develop or acquire other alternatives," Feinseth explains, like sparking water, flavored seltzers, teas and sports drinks, since "that's where the growth is, in the niche beverage markets."

Coca-Cola does offer products besides sodas, and it continues to diversify its portfolio. The company made six new acquisitions in 2018, among them coffee chain Costa Coffee. They also own popular beverage brands Dasani, Minute Maid and Powerade.

And Quincey said on CNBC's "Squawk on the Street" that the company will take time to "absorb" the investments it made last year.

On the heels of Amazon canceling plans to build a New York City headquarters, Warren Buffett's right-hand man Charlie Munger shared his view of Amazon with CNBC.

"My attitude toward Amazon is it is an utter phenomenon of nature," Munger told CNBC's Becky Quick Thursday. "There has hardly ever been anything like it in the history of our country ... very talented driven people."

The vice chairman of Berkshire Hathaway, who is worth $1.7 billion, according to Forbes, says he has been surprised at Amazon's growth.

"I would not have predicted the success that happened and now that it has happened, I wouldn't want to predict that it was going to stop either. I think it may run a long way."

Munger has also called founder and CEO Jeff Bezos "ferociously smart."

Bezos quit a steady job in 1994 when the internet was new to found Amazon, which now has a market cap of more than $790 billion.

"I founded Amazon in my garage 24 years ago, and drove all the packages to the post office myself. Today, Amazon employs more than 600,000 people, just finished its most profitable year ever, even while investing heavily in new initiatives, and it's usually somewhere between the #1 and #5 most valuable company in the world," Bezos said in a recent Medium post. "I will let those results speak for themselves."

Berkshire Hathaway decreased its stake in Apple by nearly 3 million shares, to 249.5 million, in the fourth quarter, but Warren Buffett reportedly had nothing to do with the selling.

"One of the managers other than Warren had a position in Apple and sold part of it in order to make an unrelated purchase," Buffett's assistant Debbie Bosanek said in an email to Reuters. "None of the shares under Warren's direction have ever been sold."

Bosanek didn't immediately respond to CNBC's request for comment. Berkshire didn't return CNBC's call seeking comment.

Buffett first announced Berkshire was buying Apple in February 2017 despite his usual aversion to tech stocks. And since then, Berkshire's position in the iPhone-maker has grown significantly. By the end of 2017, Buffett's conglomerate already owned 165.3 million Apple shares, and it bought another 75 million shares in the first quarter of 2018.

Buffett told CNBC at the time that he clearly likes Apple, and "we buy them to hold."

"We bought about 5 percent of the company. I'd love to own 100 percent of it. ... We like very much the economics of their activities. We like very much the management and the way they think," Buffett told CNBC's "Squawk Box."

Charlie Munger, Warren Buffett's right-hand man at Berkshire Hathaway, said that places like California and Connecticut have been very "stupid" for driving rich people away from their states.

"It's been serious. Driving the rich people out is pretty dumb if you're a state or a city," Munger told CNBC's Becky Quick in an interview Thursday. "There are a number of places that have shot themselves in the foot; Connecticut, California, New York City."

Munger was answering a broader question, in the wake of Amazon ditching its New York City headquarters plans, about whether some cities and states need to make their tax structures and regulations more attractive to wealthy individuals and businesses.

In Connecticut, "they've driven out all the rich people. California is doing the same thing. I know a lot of rich people who have left California," Munger added. "I think it's really stupid for a state to drive the rich people out. "They are old, they keep your hospitals busy, they don't burden your schools, police departments or prisons. Who wouldn't want rich people?"

California and Connecticut have two of the highest tax burdens in the country, according to WalletHub. The burden in California is 9.57 percent while Connecticut's is 10.19 percent. To be sure, California is home to some of the largest companies in the world, including Apple and Facebook. Meanwhile, Connecticut is the home of some of the largest hedge funds in the world including Bridgewater Associates.

Recently, some lawmakers have been pushing for higher taxes on the wealthy, especially Rep. Alexandria Ocasio-Cortez, D-N.Y. Ocasio-Cortez has proposed a 70 percent marginal tax on incomes over $10 million in an effort to bridge the growing wealth gap between the rich and the poor.

But Munger thinks the divide will slowly bridge itself as interest rates are unlikely to go "much lower" from current levels. By slashing rates and implementing quantitative easing measures a decade ago, the Federal Reserve inadvertently bailed out the rich to help the poor during the financial crisis by boosting asset prices, Munger said.

"Nobody was doing that because they love the rich; they just didn't have any other tools in the kit," he said. The inequality that came from that "wasn't malevolent and it was an accident and it probably won't happen again."

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WATCH: Investing legend Charlie Munger on investing, the buyback debate and much more

Warren Buffett's longtime business partner Charlie Munger is not a fan of active investment management and thinks it could harm inexperienced investors.

"If you take the modern world where people are trying to teach you to come in and trade actively in stocks, well I regard that as roughly equivalent to trying to induce a bunch of young people to start off on heroin," Munger said from the annual Daily Journal shareholder meeting on Thursday.

Munger instead lauded large index funds for the everyday investor who is looking for exposure to the stock markets and said that many active stock pickers are still in a state of denial that their expertise is worth the fees they charge clients.

"They have a horrible problem they can't fix so they just treat it as nonexistent," Munger added. "It's wrong to have all these people in just a state of denial and doing what they've always did year after year, and hoping that the world will keep paying them for it even though an unmanned index is virtually certain to do better."

Money has flooded into index funds and exchange-traded funds during this long-running bull market, while fee-based active strategies have suffered. The market for index funds has reached $6 trillion, while the market for exchange traded funds, which track indexes, has ballooned to $5 trillion since the SPDR S&P 500's inception in 1993.

Munger himself, however, is one of the most celebrated investors in history and played a crucial role in Buffett's success. Munger's investing prowess preceded his move to Buffett's Berkshire. From 1962 to 1975, Munger's investment partnership generated 20 percent annual returns versus the S&P 500's 5 percent. Read more about his investment strategy here .

Still, Munger said it's alright for investors to maintain a small number of stock positions if they're looking to outperform the broader stock markets.

"It's OK if the individual has a few holdings," he said. It's "more important to invest where you have extra knowledge."

"The whole idea of diversification when you're looking for excellence is totally ridiculous. It doesn't work. It gives you an impossible task."

Munger will speak with CNBC's Becky Quick following his annual speech.

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Warren Buffett's longtime business partner Charlie Munger will on Thursday address shareholders of the Daily Journal, the Los Angeles-based publishing company where he serves as chairman.

The billionaire Munger, who turned 95 on New Year's Day, is credited by the Oracle of Omaha for transforming Buffett's initial bargain-based buying strategy and molding it into a long-term value strategy. Munger and Buffett have been partners for about 60 years.

Munger will speak with CNBC's Becky Quick following his annual speech.

Munger is one of the most celebrated investors in history and played a crucial role in Buffett's success. Munger's investing prowess preceded his move to Buffett's Berkshire. From 1962 to 1975, Munger's investment partnership generated 20 percent annual returns versus the S&P 500's 5 percent. Read more about his investment strategy here .

The billionaire's annual comments from the Daily Journal meeting, where he takes questions from shareholders, have been shared on Wall Street among his many followers for years.

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In the HBO documentary, "Becoming Warren Buffett," the Oracle of Omaha says that there were "two turning points" in his life: "One when I came out of the womb and one when I met Susie."

"What happened with me would not have happened without her," Buffett said of his first wife, who died in 2004.

In fact, the billionaire says, the biggest decision of your life will be who you choose to marry.

"You want to associate with people who are the kind of person you'd like to be. You'll move in that direction," Buffett said in a conversation with Bill Gates at Columbia University in 2017. "And the most important person by far in that respect is your spouse. I can't overemphasize how important that is."

Young people are more optimistic than any other generation about their career prospects and the opportunities that lie ahead, despite the growing threat of job disruption.

That's according to a new study from professional services site LinkedIn, which found that the majority (52 percent) of people aged 18 to 29 are hopeful that the employment landscape will improve over the coming years.

The findings, which are based on a survey of over 11,000 people in nine countries across Asia Pacific, point to greater caution among older workers, who believe they will be adversely affected by the shifting jobs landscape. Just two-thirds (41 percent) of those aged 50 to 60 say they think their career prospects would improve this year. China was the only exception to that, with optimism at its greatest among older generations.

The findings reflect the wider uncertainties surrounding technology's impact on the workforce, said Roger Pua, LinkedIn's senior director of brand marketing and communications for Asia Pacific. However, he noted that employees of all ages can better prepare themselves by focusing on five key work skills.

Warren Buffett is no doubt one of the few business icons who can deliver the gift of wisdom and truth when we need it most. And those truths, when you really stop and consider them, are always spot-on.

In her biography of Buffett, "The Snowball: Warren Buffett and the Business of Life," author Alice Schroeder writes about a time when Buffett gave a presentation at The University of Georgia. The students asked him about his definition of success.

When you're nearing your end of life, your only measure of success should be the number of "people you want to have love you actually do love you," he answered.