I have been known to tell jokes that have punchlines that are twisted in such a way that if you don't catch on, you will think I am either an idiot, or a horrib

I have been known to tell jokes that have punchlines that are twisted in such a way that if you don't catch on, you will think I am either an idiot, or a horrible person. Two guys have fast cars and decide one day to have a contest to see whose car is faster. I can't tell you the rest of the joke though. It's racist. See, if you get it, you laugh. If you don't get it, I'm suddenly a very bad person. I told this joke in public, to a stranger, once. They thanked me for not telling them the punchline (not realizing of course that that WAS the punchline). I don't tell this joke anymore. Well, except here. But there's context.