Regression toward the mean Puns

I was out at dinner with my parents a few nights ago, though I'm only getting around to posting this now. For some background, my mom is basically the nicest person in the universe, but my dad, brother and I are all capable of being assholes on a whim as long as we think it would be funny. This came up in conversation, and we got the following exchange:

Mom: I don't understand how you can be so rude when you live with me.
Me: You're too nice. We have to balance you out.
Dad: We're regressing toward the mean.

It actually wasn't all that bad at first. He didn't over-enunciate "mean" or anything. It really only became a true groaner once he added the ultimate joke killer:

"Get it?"