QUOTE(cyberwaveIT @ Mar 30 2012, 12:00)

Crackling one's chest cavity is much harder (generally) for one to do by themselves, and yes, it definitely freaks out people, when they are not able to do so. They look at you & think " WTF?! "
I find it easy. I just lean back until I hear a crack. I know my sister can do it as well, since she was stretching once in front of some family and friends and her chest cracked, as she expected, but everyone else freaked out. They asked her if she was in pain. So I proceeded to crack my chest too and everyone groaned, as if they thought I was in pain. Fortunately there is no pain for me when I crack anything. Oh wait, there is my left shoulder, but that's a recorded injury that I know of and will keep tabs on as I grow older.