Someone very close to me committed suicide.. and I don't think he was selfish in any way.. in fact, he was the most selfless person I knew. Genuine, caring, and a bit misunderstood.
He was an immigrant who spoke hardly any English. Everywhere he went, he was pretty much outcasted. When his support system left him, he was all alone, and committed suicide. On top of that, he survived being beaten in a re-education camp from where he was from.. lots of painful stories in his life.
In the end, all he needed was someone to listen to him. I think a lot of people who commit suicide feel extremely lonely inside. All they need is for someone to understand/hear them out.