There are different reasons for suicide. At one extreme is teenage angst and a lack of perceived and understood connections between actions and consequences, not just for others, but for oneself. At the other exterme is someone making a rational decision in conjunction with family members that they don't want to have more experiences, due to something like intractible agony or a fatal diagnosis. The latter is generically termed "rational suicide". Lumping all suicide into some stereotypical notion of "selfishness" is denigrating to not just people contemplating rational suicide, but to the depressed, mentally ill and bereaved as well.

Society shames people for even thinking of suicide and this is unhelpful. It probably prevents (or more often, merely delays) a minority of suicides, but does not alleviate human suffering, and in fact, increases it.

Once again we have religion to thank for this. Christianity's notion of a blissful afterlife and an end to all suffering therein, tends to make it into a suicide cult, so early on, it had to develop a strong taboo against suicide to counteract these tendencies (and for other reasons).

I think associating suicides or attempted suicides with selfishness is bullshit. It's a concept that was created to use guilt to dissuade people from committing suicide. Selfishness is utterly irrelevant to suicidal individuals.

Suicide is associated with an illness. It's sad that people feel that their lives mean so little that their death won't affect anything or that their suffering is so horrible that life becomes torture for them. To have no hope, no joy, and no value in living isn't a choice people make it's an effect of severe depression. A lot of the problem is actually our misguided views of mental illness and our inability to understand or sympathize with those who suffer from it. The stigma attached to the condition makes people who need help reluctant to seek it.

“There is but one truly serious philosophical problem, and that is suicide. Judging whether life is or is not worth living amounts to answering the fundamental question of philosophy. All the rest — whether or not the world has three dimensions, whether the mind has nine or twelve categories — comes afterwards.”

-Albert Camus