I believe in an afterlife, but I don't think I could deal with the shame of admitting I wasted a life that so many other people on this planet are crying out to have.
So I choose to stay, and find a way to help someone else, because ultimately it will help me.
That, and my war-era grandmother has instilled in me an absolute hatred for waste of any kind.
I had a multi religious experience growing up. I was baptized Catholic, mom was raised Catholic, but we went to different types of churches.
Anyhow, somewhere in there grew the idea that your life is a gift from God and that, if you killed yourself, you would go to Purgatory, or hell. Though, on another level, I do not believe God would punish someone who hurt so bad in life for killing their selves. I am torn between the two. For the most part it has kept me from doing something disastrous.
As far as wasting life, I think, when someone dies, that it should have been me because they wanted to live more then I do. I do think that is greatly unfair to them.