What if I want to break the heart of a girl I've liked for years? I don't even have a reason
What will happen after you break her heart?
Nothing will happen. I'll be feeling much better when I push her away
But you liked this girl, so there must be a real reason you want to hurt her. Despite all of that, it's terrible to want to cause her pain when you could have just ignored her and went on with your life. You really want her to suffer?
When she finds out why, I'll see how she feels and if it makes her miserable, I might back off.
You should never intentionally hurt someone's feelings. Doing this to someone you like will leave you with regrets in the future.