3 or 4% withdrawal but what if market tanks??

If your expenses are 3 or 4% of your assets the conventional wisdom is that you can retire. But what if the market tanks or goes sideways? How do you sleep at night? I know long term things should be ok if historical market performance continues but I’m just wondering how people manage this psychologically? It would be one thing if I could generate living expense money from bonds but that would require a lot more money.