When CNBC's Jim Cramer worked at a hedge fund, his boss would make him wear a "Post-It note of shame" when he missed a good buy or gave up on a great stock.
"Many of us should be wearing a collective Post-It if you sold [these stocks] during the big panic," Cramer said. "Remember, if you have conviction, if you believe in a company, you use the declines that we had today to buy the stock, not to sell the stock."
Cramer began with Boeing, applauding its "unbeatable product" and many tailwinds. The aircraft manufacturer's order book gives the company visibility 20 years into the future and the opportunities with consumers are bountiful.
As Boeing CEO Dennis Muilenburg told Cramer in December, over 80 percent of people in the world have never flown on a plane, and for Boeing, that means growth.
Moreover, Boeing has been buying back swaths of its own shares — a boon for both its shareholders and its stock price.
"None of that changed when the market went into a tailspin," Cramer said. "Boeing's book of business wasn't hurt by a little wage inflation or modestly rising interest rates or margin calls in the financial markets."
"The stock is headed to $400," he reiterated.
Next, Cramer turned his focus to Amazon, the e-commerce giant taking on nearly every corner of online retail with a cloud business kicker.
With millions of U.S. consumers now subsisting on regular Amazon Prime deliveries, Cramer said Amazon's rally should've been easy to catch and stick with.
"Did you get washed out of Amazon because you heard that Fed chief Jay Powell might be a little worried that the economy's too hot?" the "Mad Money" host said. "That's called a mistake. That's why you need conviction, so you can stick to your guns."
Finally, Cramer addressed one of his favorites: the stock of Apple. Shares of the iPhone maker tanked after the company's earnings report nearly a month ago before bouncing back to record levels on Wednesday.
While Cramer wasn't sure if selling Apple amid the decline warranted a shameful Post-It — after all, the company's smartphone sales growth is slowing — he lamented about Wall Street's coverage of the stock.
"Apple's a consumer product company with an incredible following that's created a beloved technological ecosystem, second to none, with the highest customer loyalty of any device in history," he said. "Procter & Gamble, Clorox, Colgate, Coca-Cola — they ain't got nothing on Apple, even as their stocks all sell at dramatic premiums to the incredibly cheap stock of Apple."
"The problem is that Apple's covered by tech analysts, not consumer product guys, which is part of why truly brilliant people ... end up making mistakes about the stock."
All things considered, Cramer asked investors not to be discouraged during market downturns like investors saw late in the day on Wednesday.
"Look at what worked through the month," the "Mad Money" host said. "These stocks all bounced and bounced hard from the last market-wide sell-off we had and you know what? I bet they'll bounce again from the next market-wide sell-off, whenever it happens."
Disclosure: Cramer's charitable trust owns shares of Apple.