I feel like this relates a bit to a quote from Kevin Smith (silent bob)
To paraphrase, you have to be a little bit delusional to think you will succeed, otherwise you won't get started. You won't make the big risky decisions that bring you to success.
Which I relate to a second thought of my own which is, what will I regret if I hadn't at least tried?
Which together, help motivate me to continue game development. There is just so much work to be done, and you have to just assume you'll be good and succeed at half a dozen different disciplines to bring it all together.
I think this is one of the biggest reasons why USA has so many succesful companies. People in there are taught from birth that America is the greatest country and they are great and everything is fabulous and everything is possible.
They are delusional about their capabilities and sometimes that's the magic sauce you need to succeed - infinite confidence.