I enjoy moving air bubbles caught between my joints that are displaced by the rubbing together of my bones in a quick action. I do it when I stretch before excercise and after waking up, but not any more, otherwise I could risk arthritis at a later age.

No one can vote in the "they never crack" because it's impossible for them to crack at an age where you can actually access the internet by yourself. Well, if they never cracked, then that means you wouldn't be using the internet anyways, Mister Jock, now would you?