Anxiety is the same way. Sometimes anxiety helps you to be careful and that tends to reinforce itself and you think that you have to be anxious in order to succeed.
Success can be relaxed and enjoyable. It does not have to feel stressful and like it is going to kill me.
Winners attitude without over-optimism is a balancing act. Call it confidence!
Good habits can lead to confidence, repetition of success with a habit makes for repetition of a habit.