I shorted SPY at 82.72 with a .30 stop at 83.01 and canceled the stop because I thought I could get out even only to get filled on the stop at 83.20. I also shorted stock around the top of the spike and made most of my money back in a few minutes. The rest of the day turned out pretty well.
Company profits? Reasonable? Realistic? Remember that as a trader, you aren't so much trading the news as you are people's reaction to the news. Perception is reality. And you're right, human nature doesn't chage, which is why trading will always be around as a profession. Although some people seem to think the last 6 months have negated hundreds of years of repeatable patterns.