I honestly think now that staying committed to finishing a task and all of its small or intricate problems that come with it really comes from putting in the hard work and also being positive. This positivity will help you stay self-confident and engage a working brain for all the time you need to finish it.
For myself, what gives me this sense of happiness while being self-confident and pursuing after being a daily problem solver to make a living is putting my trust in Jesus. I simply just believe in what Christ did for me on the cross and it's enough for me to desire being one of his followers. I try to tune into listening to the Bible daily, so that's how I mainly get all the spiritual food I need to grow. It's remarkable how it's really had a very positive effect on my life. I don't even have a calling to be a Pastor of a successful church. I wouldn't even want to begin on it!