I don’t think there is any one lesson that everybody should learn.

I think life is different for each of us, and what we need to learn from it depends on who we are and how we want to live our lives.

This might be unsatisfying, but if you look at it another way, you’ll realize that there are at least as many life lessons as there are people living. There’s an infinite universe out there, and you’re in it, with no limit to what you can learn and where you can go.