You need that self-discipline to make sure that you will practice whatever you setup before playing, else, you will messed around.
Once excitement is already there, to me, it gives me the thrill and wanting to gamble more. I'm losing my self discipline with that but it knocks me out whenever I start to have a losing streak. It's good on my end that it wakes up whenever I feel that way. Because setting up yourself before you gamble is needed that you'll have your own book and rule to follow. Easy to say sometimes that we can control ourselves but, once you're already on that momentum, I doubt that you'll have that control anymore.
When that understanding is there and you apply discipline, no matter how excited you are, it will never lure you to gamble more. Normally, when you win in gambling, you will surely feel excited; it is a feeling that you can never hide. But for those who don't understand gambling, the excitement can lure one into gambling more because one might feel more wins can be achieved.
Controlling oneself in gambling depends on understanding and discipline; it doesn't really depend on excitement because some people still feel excited about gambling, but they control themselves.