I think it's helpful to look at the emotion as an indicator and not an obstacle to be overcome. It's a warning system indicating that there's an imbalance for example, by just trying to ignore / 'fight' negative emotion you just amplify the original emotion. I think it's best to just aknowledge it for what it is. The key is not be judgemental (of yourself, or the emotion) and just watch it - the effect of standing back from yourself and assuming the position of observer is quite powerful.

I think at the end of the day whatever means people use to find their 'inner strength' thats the best way to conjure discipline, especially in the heat of a testing situation. Personally I have found speaking to God has helped me quite a bit. =)