I think when you're down and suicidal, focussing emotionally and intellectually on suicide is a coping strategy that helps you deal with whatever it is that is making you suicidal by reminding you that there is an exit. And there should be an exit (stay away from religions telling you to suffer in silence and that suicide will buy you an eternity in hell, don't listen to evil minds). When you're normal, focussing on suicide is an emotional outlet that reminds you of your suffering (and maybe makes you think about the people who would miss you if you die?) so it makes the tear glands go wet.

Edit: I meant you as in people, not you specifically. Sorry.