I love rare meat. Rare. Bloody. Get me a cut of filet mignon and put it on a hot grill for 15 seconds on each side. Serve it to me and I won't be happier, you'll see me scarf down that cut faster than you can say, "dude you should seriously consider not eat-" but I'll be done by the time you get to finish the sentence. That's how much I love rare meat, no offense to anyone who's vegan/vegetarian.
There are some people, however, who think that it's a good idea to try the rare/undercooked meat concept to different types of flesh. Technically you can do that with fish, like sushi, but eating a properly prepared piece of sushi won't kill you.
Undercooked chicken, on the other hand, can. This is something that pretty much everyone who's ever learned anything about food can tell you.