I suppose in certain situations, where the person in question commits suicide to escape from something, and leave behind major problems for people around them to deal with, (things like debt, children, etc.) suicide can be considered selfish.

But, in general I get really angry whenever anyone refers to suicide as selfish, especially in a negative tone. My logic is, if they are truly miserable and want to go, it is generally more selfish for those around them to try and stop them because they don't want to be troubled. It is a choice that belongs to them and no one else. However, it should be noted that they should try to get the person help to try and combat their feelings. Not for their own benefit, but for the benefit of the unhappy person in question.