"Every few weeks some old-timer or hot hand comes on air and yells 'fire' in the theater," the "Mad Money" host said. "I get it. Look, these statements about the market being too high roll off the tongue so easily. ... The bears sure were right today, right? They could be right again tomorrow. But that doesn't mean they could be right over the intermediate term, which is the term that I like to think about."
Cramer said that some fears, like those of the tensions between the United States and North Korea, are legitimate. But the slew of illegitimate worries about stocks being overvalued and on the verge of collapse need to be addressed, he said.
First, Cramer acknowledged that some stocks are overvalued. Many of the big consumer products names sell at 20 times earnings, a costly price even for stocks with good dividends.
"But their dividends are often much higher than Treasurys and Treasurys give you no upside whatsoever, so what are you supposed to do? If you choose to hide in Treasurys while these stocks, I'm talking about Clorox, Procter & Gamble, frolicked higher, you've missed out a big run. Where I come from, you know what they call that? A mistake," Cramer said.
Some of the expanding technology sector is overvalued, too, but almost every facet of tech, whether it be biotech, semiconductors, or cloud, has taken a turn at being pricey, Cramer said.
Two years ago, Facebook traded at $98 a share. One year ago, it was at $126. As of market close on August 10, 2017, the stock was priced at $167 a share.
Amazon's run was even more dramatic. The stock was said to be expensive in 2015 at $478 a share, in 2016 at $790 and now, at $956 as of Thursday's close.
"Hey, maybe 'expensive' doesn't mean 'sell, sell, sell,'" Cramer said. "The most disciplined thing you could've done with these stocks was to stay long through all the jeremiads by the graybeards to get out of them. You had to tune out the sirens of skepticism who said they were dangerous."
And, to be frank, Cramer said he feels like an idiot having missed the monster runs of Apple, Amazon and others because his CNBC contract prevents him from investing in stocks.
The "Mad Money" host owns Treasurys instead, which might seem like a smart move to the bears, but has just made Cramer feel like he sat out on some of the market's greatest runs.
"I keep coming back to one major issue, even as I expect the market to go down [on Friday]. Almost every winning stock I've mentioned was overvalued, classically overvalued before its run," he said.
Cramer recalled to when Apple, at $93 a share, was possibly the most overvalued stock of all time.
"I can show you analyst after analyst who told you that stock was going to get crushed because earnings were going to be down in 2017," he said. "Oh yeah, that's right, the stock went to $160. But they were smart."
"Listen to yourself," he said. "Do your own work. But understand that it takes a ton of discipline and conviction to own a Facebook or an Amazon or an Apple through these runs, and you aren't an idiot if you do. You're smart. In fact, I have one word for you: congratulations."