But that kind of belief doesn't foster the mindset of "if I fail, that's just life and I will move forward." Having that much confidence in accomplishing something means staking my self-worth on it, because this is a test of my own effort and nobody else's. The results begin and end with my actions only, and the things I want are too important to me to not take seriously. If those things are what I ultimately want to spend my time on Earth succeeding in before I die, then not succeeding is devastating to my mental health.
I don't understand how not to think like this, because every real success I've fought for and won came as a result of believing my life was over if I didn't succeed. In some cases I really would become poor or have no future if I didn't succeed, so it grants too much legitimacy to the method.