At the 2020 Berkshire Hathaway annual meeting, Warren Buffett speaks about (transcript) on the trouble with probabilities is that just because something should happen doesn’t mean it will.

I don’t know, and perhaps with a bias, I don’t believe anybody knows what the market is going to do tomorrow, next week, next month, next year. I know America is going to move forward over time, but I don’t know for sure, and we learned this on September 10th, 2001, and we learned it a few months ago in terms of the virus. Anything can happen in terms of markets, and you can bet on America, but you got to have to be careful about how you bet, simply because markets can do anything.

Buffett used airlines as a example—What looked like decent investments turned out to be a dud because the most unlikely event actually happened.