This topic always opens up a can of worms.
It is possible to look at suicide as an act of selfishness from a certain perspective.
However, some of the posts above mine seem very narrow minded.
Not everyone has a strong family support system to love them and coddle them when they feel like crap.
Sometimes I feel it's even more selfish for family members/friends to try to stop someone from committing suicide (over something really huge, not just being bullied at school), because they don't want to feel like crap after that person kills themselves. Though with my response, there are many different things that come into play and stopping someone from killing themselves doesn't make you purely selfish, but it can be looked upon as such.
And while there can "always be an answer", I sincerely doubt most of us, have gone through a time when we've really hit our lowest point. If anyone of you, have and you're still alive today, I commend you, but you're live is yours and though killing yourself can be "selfish", everyone has their breaking point.