Yes, they're motivated and driven students, but it's also a big game..... I've played "the game" myself (not in dentistry, lol)-- and yes, to an outsider looking in, the keeners look like freaks. It's really difficult to keep your life in balance-- as your field of study can become your only outlet for socializing, recreation, etc.
These kids will become normalized sooner or later--- after they graduate and get on with their lives.