What's a spiritual truth that took you way too many years to grok but your life is so much better now that you get it?

Noncompetition is a virtue in Taoism and it took me a lot of my twenties to really break from a competitive mindset (my financial survival depended on getting the best grades for years) and rid myself of any desire for comparison. I'm much more at peace since I let it go.

Another spiritual truth that I grokked pretty heavily when I was reconciling with my alcoholic parents through recovery was that forgiveness isn't for the person being forgiven, it's for the forgiver.