Our natural response to suicide is to feel sorry for the person who was so tormented that they chose to take their own life.
That compassion is good because it reflects the love Christ said we should have for our neighbors. Someone who kills themselves is no less deserving of our love than they were before they made that horrible decision.
However there is a risk of encouraging more suicides if we lose track of the bad aspects of suicide.
From a theological sense it's a sin though clearly many, if not nearly all, people who commit suicide are not mentally competent and hence not capable of sinning. In any case it is for God to judge not us and we can only pray that His infinite Mercy will bring the troubled soul to Him for eternal rest.
But even from a purely secular perspective suicide hurts people.
The person who kills themselves leaves their family and friends with a huge amount of trauma. They also leave whatever problems were bothered by for someone else to deal with.
Once again if the person who kills themselves is not mentally competent, which is often the case, they aren't responsible for the havoc their action causes. The purpose of pointing this out is not to condemn those poor people who kill themselves but to deter those who would follow in their footsteps.
These are hard words but they are needed for those who are contemplating suicide and who are mentally competent. In our world it's easy for people to think that suicide is ok, even to think that others would be better of if we were dead. Yet that's not true.
God has a plan and it doesn't involve killing ourselves. When we go against His will we cause pain and suffering. That's inevitable since His will is motivated by unlimited love for us.
When we think there is no other option we need to seek help and seek out others; we are not islands.
Anyone who is contemplating suicide needs to think about others not themselves. That will not only spare families and friends from suffering but it will spare the person themselves by giving them a chance to overcome the sorrows that are driving them to contemplate suicide.