Perception is a ship without an anchor, tending to drift. How we perceive ourselves can often change in an instant, but ultimately there are core beliefs of who we are that form a foundation that is seemingly unchanging.
Poker is a thorn in my side, pricking me every time i play, reminding me that one of my core beliefs isn't so solid, the belief that i am a disciplined person. Learning self discipline enabled me to control my anger, it got me through grad. school and allowed me to play rugby at a competitive level. Yet when it comes to poker i am totally devoid of discipline. Why? I think its a matter of scale.
It's easy to be disciplined when there is a consequence. Its the corner stone of any child's upbringing. It's the only thing that keeps society civil. We are inherently selfish creatures. In poker terms we are level 0 creatures. Level 1 is learnt. We would not have evolved any other way.
True self-discipline is the ability to turn it on and off at will, independent of consequence. Poker has taught me that i am not a disciplined person.