Efficient Markets

So how does someone like me with all the emotions and temptations of every other man on the street get to manage a significant portion of some one's retirement assets? This week I think I behaved more like a novice than most untrained e*trade account holders. Lucky me, I escaped with only minor injuries but I know i got off the reservation.

So looking at my performance this year, I am beating my boss.... but is that just luck (possibly Bill's bad luck) or actually due to skill. Also looking at the last 3 years, I have beaten the market by a decent margin, but again that could be due to taking more risk and is still a short period of time to decipher whether it is skill or just "being in the right place at the right time."

But the question remains: Why do I overtrade when I know that i'm not skilled as a short-term trader and that I often mute my gains by trying to capitalize on a short-term move. Am i just too stupid to learn from mistakes? Am I so adventerous that I have to take risky trades to feel like i'm enjoying the job? Or am I so competitive that I feel i have to exploit EVERY opportunity to try to gain an edge and post better returns?

I REALLY REALLY WANT TO DO WELL!!!! So how am I going to cut back on preventable mistakes so I can develop that enviable long-term track record?