Discipline,
Self-programming is the hardest thing that I've ever had to do in my life. Once you get into a bad habit, it is really hard to get out of it.
However, entire personality changes are downright brutally hard to enact. I think it is human nature to think that we are all perfect in our own ways. We might not thing we are perfect consciously, but subconsciously are minds don't want to change a thing.
I have daytraded here and there in the past, and I was a victim of human impulse. I don't know how many times I bought the high of the day simply because the price started running up and I got all excited and started to shake and click the mouse like a madman while thinking, "oooohh ohhhhh!!! OHHHHHH!!! It's going UP!!! OHHHHHHH GOTTA BUY IT ! IT'S ROCKETING!! OHHHhhhh ohhhhh ohhh!!!"
I'd lose my cool approach and turn into an emotional monkey that would click, type and work my way into a frenzy. Then, as soon as I bought the HOD, it would turn around and I'd again start shaking the mouse around while thinking, "Ohhhh Ohhhhh Ohhhhhh!!! OHHHHhhhhhh SHIT!!!"
At the end of the day I told myself that was stupid and I wasn't being cool about it. So I said I'd never do that again. I then did that the next day. So then I stopped for a bit and just learned to watch the price action and, when it started making a serious run, I learned to control my emotions by not reacting to the event. It was REALLY REALLY hard.
I think anyone who suddenly sees a major breakout or the price-action on the tape can get a little hyper and crazy about all that action.
However, you are exactly right. Discipline is a hard thing to develop on your own. You also just can't make personality modifications like that without making them throughout your entire day. You should always concentrate on the here and now and try work on your bad habits throughout life -- not just in trading. I quit smoking because it was a really bad habit that I'd develop when things got very stressful in my life. Now when I get stressed out, I go to the gym and run it off on the treadmill.