People are different. Some are thrill seekers, behavior which shows up in a psychological profile, as well as a driving record. Turns out that it also shows up in a brokerage statement. People who are thrill seekers are more likely trade more frequently, less likely to be buy-and-hold investors, according to a recent study by Mark Grinblatt and Matti Keloharju. Over confidence also leads to more trading.
In my speeches about "What We Have Learned About Investments Since Enron and the Tech Collapse," I emphasize that good investing requires going against one’s emotions. Apparently, it’s worse than even I had thought.