Ask HN: Is the stock market different this time?

The stock market is at all-time high and this last bull run has been the longest in history.

However, I'm increasingly nervous that a big downturn is around the corner and am considering moving a significant portion to bonds. COVID is still ravaging my local economy and I'm concerned about the new variants.

But when I poll my friends, everyone seems to be super optimistic and pouring even more money into the stock market - and they're reaping big gains!

Do you think a significant downturn is coming (as has followed all major bull runs in my brief survey of history)? Or is something fundamentally different this time about this bull run that I don't understand?