The company I'm currently CTO at I had founded when I was 23. It's now a multi-hundred million dollar company, growing very quickly, and about to cross 100 employees. I've learned a lot along the way, but I've especially learned from managing parents. As I started managing parents and realizing how much they base their own values on how their children would think of them and their life principles, it became apparent to me that this is how I want to live my life too.
I have struggled with depression and anxiety from an early age, so, when I start attaching to an overly-cynical view of how the world operates, I ask myself "Do I need to believe this is how the world operates? How does this serve me? Would I want my children to embody this world view?". If the answer is no, then I try to have my world view serve me and end up much happier and actually much more effective in the long run.
I've come to realize you have to be a bit of a pessimist when understanding how things "really work", but going about your life as an optimist and working around the structures is just as important if not more so for people like myself who were born with a broken operating system.