Depends how it's done. I guess I'm one of those people who doesn't like "bad" endings unless it makes sense and you deserve it. Like if the option is "save this kitty or massacre an entire village of people and sit on a mountain of corpses" and you pick the second option, well you kind of deserve a bad ending imho That poor kitty never got saved
My favourite is multiple endings were none are necessarily bad or the BEST one, but just different. Take a different path in game life, end up somewhere different. Make a different choice, get different results.
I don't like when they're a pain to get but if I like a game and they aren't too difficult, then it adds some good replay value and you can discover something new, which is nice