What would you like to let go of?

I find that I tend to carry around a lot of useless regrets.  I regret that I didn't say more to my grandfather the last time I saw him alive.  I regret that I didn't visit my mother more in the last couple of years before she died. I regret letting a bunch of punks pressure me into insulting a girl I really liked back in high school. I often wonder how things might have turned out if I'd actually done the thing I regret not doing, or not done the thing I did and regretted.  I know it would be healthier to let all these regrets go, but that's easier said than done for me.  How about you?  Is there some regret, something that happened to you, something you did, didn't do, etc., that you wish you could just let go of?  What is it? How has holding onto it affected your life?