This is usually an annoying decision. The Chinese immigrant in me is willing to take the bus across SF instead of a cab, in order to save $10. This decision will impact slightly more than $10, which makes me feel compelled to do a massive amount of research -- read all the quarterly reports, compute projections, etc.
Luckily some of my friends have a good attitude on it all.
Googler #1: [looking at stock price of $600] Maybe selling at $200 was a mistake.
Googler #2: Not buying MSFT for $0.11 in 1986 is a much worse mistake. Also, you should have named the winning lottery numbers in last week's Powerball. Hindsight is 20/20, the market is random, and we're all lucky fuckers.