8. Cracking up
It would be interesting to know how many children were admonished when they were caught cracking their knuckles, and informed that it would lead to arthritis later in their lives. This one goes down in flames with the rest of them since there is nothing to suggest it is true. Some people find the sound of cracking knuckles unpleasant, but the reality is that it will do the perpetrator no ham. It’s simply the sound of gas bubbles.