This is a difficult question to answer.

On one hand, I don't have a lot of regrets; my life hasn't ever been really great, but it's never been particularly bad either.

But on the other hand, there a lot of little things I wish I had done differently: Wish I wouldn't have been late to work that one time so I didn't upset a manager who was already in a poor mood, wish I had been a bit more consistent with projects I had set out to do, wish I had been just a bit happier when people were relying on me for strength.

To answer your question though, I'll say this:

I wish that my best friend and I never had a "lightsaber duel" when we were kids. What happened was that we were playing with those plastic lightsaber toys that do that extend thing when you hold down this button on the side. We were having a battle with them and I accidentally hit him in the face. It was not on purpose. Because they were made of plastic, when the sabers were locked against each other, his slid down off mine and mine kept going and hit him right on the side of his face. He cried. I had never seen him cry before.

I don't think he ever forgot it, nor did he ever forgive me for it, even though it was completely accidental. Sure, it had been my idea to lightsaber battle in the first place, but I don't think he ever forgave me and I'm almost certain it was a big reason for him choosing to no longer associate with me.

He was my best friend; we were so close until that day.

So yeah, if I could go back and redo one thing, it would be to not have that lightsaber battle.