Why do most people believe that suicide is a terrible thing to do?

People commit suicide because they can no longer handle the pain of living. Why would anyone want to stop someone else from killing themselves when they just want the pain to stop? I'm familiar with the phrase, "Things can always get better." However, my life experiences have proven that statement to be a fallacy. Things don't ALWAYS get better. Most often they get worse. I'm well aware of the religious arguments against suicide but they are meaningless to me. I'd rather hear more meaningful answers. Since the question will undoubtably be raised, yes, I am considering suicide as an option for myself. Before you lay into me and tell me my life is worth living, I must remind you that you do not know me. You have not experienced what I have experienced. Yes, I'm sure you have experienced hurt in your life, too. However, you have not felt my hurt. If you had, you likely would have killed yourself already. Most people would have. Anyways, why do so many people object to suicide?