How do you react to a break up?

I know we're all adults here, but sometimes during a break up, even the most mature people can revert back to their middle school days.

From avoiding an ex to talking bad about them behind their back, break ups can cause seemingly normal adults to become catty and paranoid. Personally, I avoid my exes. It doesn't matter who did the breaking up. I can think of possibly nothing more awkward than running into an ex, pretending nothing happened and be like, "Dude, what's up?"

I have friends who will take no time in telling off the person who broke up with them. After I was wronged by one guy, one of my girlfriends offered (in jest, I'm sure) to slash his tires. Some people cry for days. Some decide to start completely anew and change their look. Others embark on ill-fated attempts to win their ex back.

Love -- and more often than not, lust -- can make people do some crazy things. I once hit an apple with a tennis racket and pretended it was a guy's head. (This was not my idea, but it was a therapeutic one. The apple went pretty far. Although it did not explode like I expected it to.)

How do you typically respond to a break up? What's the craziest thing you've ever done as a result of one?