My Knee is Sore

Can someone please explain to me why people slap their knees when they laugh hard?

Is this some kind of genetic response, human reaction, or can we blame the Republicans on this one. (I'd like to blame the Republicans on this one!)

Everyone knows someone who slaps their knee when they get a good laugh going. But why the knee? Why can't we tap our heads or rub our tummy's. Why slap our knee when we have so many other body parts to slap.

Why can't we be like the Pillsbury Dough Boy...where we get poke our tummy then rub it while laughing? Not only would that be even more funnier, but it takes talent. Imagine poking yourself in your tummy while laughing...then, rubbing it right afterwards while still maintaining that laugh. You have to burn at least 50 calories, and come on...everyone loves the Pillsbury Dough Boy!

Whenever my friends (or my boss) says a really corny joke, I say sarcastically, "Wow...now that's a knee slapper," and people take that as a compliment. Now I do not know if the quality of jokes in America have been digressing, or that knee slapping is now a custom trademark of a funny joke but I say nay nay as a compliment.

But back to my root question, why slap the knee? I have seen people slap their knee when they are standing and laughing! And people grow into knee-slapping right. Nobody does it when they're young, only when you get older and it just happens!

Why can't we stick with something like the liquid coming out of your nose? Come on...you know what I'm talking about! It's when someone is drinking something while laughing, and they are laughing so hard...it comes out of their nose! If you haven't seen or experienced this...it is by far one of the most funniest things you will ever see in your life! Trust me...especially with milk, because no one can hide milk gushing out of your nose! (**ONLY FUNNY TO THOSE WATCHING THE MILK COME OUT SOMEONES NOSE**)

Wow...I am way off topic.

But seriously, why the knee? (Damn those Elephants! Damn them!)