This is the No. 1 mistake that traders make

We've all seen or heard of them — the traders who can't take their eyes off the market, who wake up in the middle of the night to check stock prices in Asia, who obsess over every basis point move.
And that obsession, for many, is their downfall.
"Whenever I see a prospective manager who says, 'I eat sleep, and drink the markets — it means everything to me,' I know I have a vulnerable person on my hands. I know I am going to be very busy," Dr. Brett Steenbarger, an associate profess