About a month after I started investing in index funds the market crashed. At the time, I panicked and didn't buy shares for a little while, like I should have and had planned to do. Looking back, the market has not only recovered, but has made that market crash look largely uneventful in the big scheme of things. Pick a plan and stick with it (low-cost index funds purchased periodically is what I do, besides a few other things).

I have a friend who is just getting around to establishing an investment account at the moment. Since the start of 2022, the markets have been down a bit, and I've lost a bit of money since the peak (if you count peaks as you having money, which it isn't. The price is only relevant when you sell), but I'm still well up all things considered.

It has got me thinking though, if you think about the perspective of someone starting today, I would still definitely do what I am doing. I just wish I had had the confidence way back when to stick to the plan.