Because this website doesn't have enough posters as it is, the last thing we need is one less.
In all seriousness though: because the people who actually do like you and do care about you, whether you know they do or not, will have their lives irrevocably changed for the worse. Even if continuing to live blows, the best thing you can do is not make it blow even more for countless other people. And there's always the chance it'll blow less in the future, even if you can't currently see the means by which that might happen. Cheer up anonymous.