Well... I regret nothing. Not because I'm perfect or something, no. I did many shit, but every mistake I did had a reason. Because I didn't know things I couldn't know, because I had that emotions defined by my personality, because I was who I was. And every failure gave me a lesson which became a part of me and made me who I am now.
I'm a damned sinner and every sin of mine is casted in iron. I'm not proud of them, but I accept and forgive myself as is.
Sorry if I'm breaking the rules of the game, I could just say nothing, but it's kind of important topic for me.