I have a theory about this. About why our childhood was amazing. It's because we never had something back then to look back on and feel sad about. We lived in the moment. We had our entire life ahead of us.

It seems like it is inevitable that we develop nostalgia and feel bad about missed adventures because we often look in the rear view mirror when we are grown up. But this raises interesting questions: are our brains; reaching the end of their growth spurt, start reusing existing structures and thus we can only live by comparison to our childhood? Is it possible that if we figure out how to allow the brain to continue creating new neurons we can feel as excited as children all our lives ?