...was in 1933, at the Height of the Great Depression! Those dummies who panicked and sold their shares during the Crash of 1929 would have been smarter to just let their stocks sit, and not sell them. You can't lose money on a stock that you don't sell!
What if the company you bought stocks in declares bankruptcy and goes out of business? By the way, I do an eye roll whenever someone brags about the number of times the stock market has broken a record in the last year, or whatever time period. The highest the DOW got was 29,551.42. That means technically it set 29,551 new records at some time or other in its existence. More, if you count pennies.
Having worked for some of the largest financial places..Merrill Lynch and etc. ..I agree for the most part. Better to buy than sell...buy low sell high .