When I was young (17 or 18, before I left home) I was depressed to the point of contemplating suicide.
I thought my suicide would be a great occasion for reflection. That my family, friends, entire milieu, maybe even society as a whole would have to consider all the things that led to this sad outcome. They would understand my situation in ways that I was unable to, and maybe even make some positive changes.
Thank God I've arrived at a much better place, and although I still struggle with depression my life is better in every possible way.
Over the years I've had a friend and a few acquaintances commit suicide, and I've slowly realized that what I hoped would come out of my suicide never happens, with anyone's suicide, ever. As soon as someone actually commits, everyone around them considers the situation just long enough to invoke the disease model and determine that they were out of their minds, irrational. None of their obituaries mentions how they died.
It makes sense. Only a crazy person would kill themself, so if you kill yourself you must be crazy. They do not consider that the person was living in a hell that was only partly made by them, and partly made by the people around them. But I do not begrudge anyone for overlooking this- grief is for the living.
If I could address my high-school self, after-school special style, that's what I'd tell them: people will be sad, but no one's going to get all 'Man in the Mirror' and make a change. Abusive people will keep being abusive, absent people will keep being absent.
It's bleak, but it would've made a difference. I didn't merely want to end my suffering, I wanted to affect positive change. I knew I would hurt people in the short term, but I hoped in the long term that people (and society, how grandiose!) would be better.
I didn't realize that suffering isn't enough. If you want to change things you have to be around to change things. Of course there are situations you cannot change on your own. I needed help with depression and a great many other circumstantial things. But if you hope that your suicide will make the world better, I guarantee it won't.