Huh, that crab story reminded me of something. It's not really much of a secret though...
When I worked in a restaurant, I would sometimes have to help out the chefs (I was just a kitchen assisant, about the lowest rank in the horrible wonderful world of cooking) when they were pressed for time. One night I was asked to prepare a lobster because the chef was busy cooking steaks. So I went and got it out of its tank and I was supposed to kill it, but I just couldn't do it.
Thing is, when you prepare live lobster, you hold a cloth over it to make it relax, then take a big kitchen knife and just crack its shell open from the back, spilling little lobster bits all over the place. While it's alive.
I know it's probably just reflexes, but it usually twitched while it was in the oven, all stuffed with butter and garlic. Eugh. I really hated seeing that every time they did it.
A bit hypocritical, since I eat meat of any kind, I just think it seemed like an unnecessarily cruel way to kill them.