Years ago there was a series of books on "Thinking of Numero Uno"--or the benefits of self, self, self. Self obsession or greed was touted as in a nutshell a powerful economic tool.
Recently in an interview with one of the "Hedge Hunters" a group of super traders, there was a profile of T.Boon Pickins, one of the famous oil speculators of all time. The author of the book on these people stated that the key quality of T.Boone Pickins was that he was "SANGUINE" on the market at all time.
To be sanquine, is to be detached. Whether you use ZEN or whatever meditational technique, being sanquine is key. One must know one's position, but also know the position of everyone, and most importantly, the party who is in the opposite side of each trade. If you have a tremendous understanding of that person and the position, when the facts change, you can adjust in a heartbeat. If, on the other hand, one is emotionally invested in a position, one is destined to lose.
Thus the irony--when you are your brother's keeper....or at least have compassion....or maybe even knowledge of the opposite---one has the ability to be a great trader.