It seems to me that when you make money by investing, you can never really know if you are lucky or smart. But of course, we'd rather see ourselves as smart, a

It seems to me that when you make money by investing, you can never really know if you are lucky or smart. But of course, we'd rather see ourselves as smart, and the ones who see themselves as lucky are not going to want full-time jobs on Wall Street. So if a bunch of people make investment decisions over and over again and get rich (or make their employers rich), they will see themselves as very very smart. When the market reverses and wipes them out, most of them will see themselves as very very smart people who just had a little bit of bad luck. Thus, one damn bubble after another.