I think many of you have the right idea. I believe it all starts with an instinctive nature. I'm a very introspective person, so after 20 years of doing this I've come to many conclusions about my own behavior. I've been a sports fanatic my whole life and I've had to learn how not to overlap my sports instinct with my trading mindset.
What has helped me in sports? Get meaner, more aggression, revenge, seeking the thrill of the score or the crushing knockout, get as many "highs" and glory as possible, challenge the inner ego, use fight or flee to one's advantage, "WILL" the outcome, are some of the things that come to mind...many of which are devastating for a trading mentality! In sports, I have no doubt that a dopamine rush in the brain is controlling the here and now. Even though many of you never played sports or have an aggressive personality...I believe we all have this instinct to not be left behind or without some edge to make sure we eat and mate...it comes out in different ways now...getting a higher grade than others or arguing on ET or whatever!
What do I do now? I use my "sports" personality and aggressiveness to discover any edge I can get, but I become a rigid machine when it comes down to execution of any setup...I leave ego and dopamine (don't want the "high") and glory and being willful and whatever out of the equation as much as possible!
I've had this thought for quite some time. If I was a trader WITHOUT a unique edge, let's say, and my methodology was very basic/simple with a good R:R of profit3 to loss1. So I trade all year with discipline and having many losses and fewer excellent gains for profitability of $3000 gain for the year...I'm considered a profitable trader...right? But what is my mindset for the upcoming year? Am I going to be impatient because I spent a whole year losing a lot of battles to barely win a war? Does instinct/ego look for more of an edge or do we remain patient/mechanical with the current profitable method? Maybe even worse, we stick with current method, but start second guessing it and sabotage it to hell. Basically we lose patience, we want MORE...it's our instinct to have an edge over others in life, trading or whatever. I believe being profitable is not enough for most traders...we want way more...slightly above average isn't going to work, it doesn't guarantee survival enough...our innate programming is running the show! My 2 cents.

P.S. Even though I eventually learned how my personality can get in the way of my trading results, I still believe a trading "edge" is most important...but you have to have both!