If you ever want to really get back at someone, don't hate them- just don't care. Hating someone and wasting the energy on wanting to get back at them just gives them the satisfaction of knowing they've won. If you really want to get back at someone, just stop caring. It drives people crazy. All we want in the world is to feel like we are important to other people and that we matter. Hating someone tells them that they matter enough to you for you to still think about them, talk about them, and consume your life with them. Hating someone will only drive you crazy, it won't make a difference to the person you hate. But being indifferent strips people of their importance; it makes them feel like they mean nothing to you and that you could care less if they exist or not. See when you actually break it down, indifference is way more effective and hurtful that hatred.
It's the same thing with ignoring someone. Responding to a text message, a phone call, or any form of communication shows that you are willing to put forth the effort to put together a response and then get the message across. It shows the other person that they are worth something. When you ignore someone's texts, calls, and messages, you send a message loud and clear: "YOU DON'T MATTER." It's more painful to know that someone doesn't even find you important enough to respond to than to find out they've been talking about how much they hate you. I mean if they're talking to you, at least they find you important enough to respond to.
Trust me from experience, being ignored sucks. Not knowing why you are being ignored is even worse. It's like when you get a D on an essay you spent weeks working on and your professor or teacher won't even tell you why. The unexplained is what drives people bonkers. We all look for a reason. Always. We all say that we believe that everything happens for a reason- and I'm sure it does- but why can't we ever figure out what that reason is? See, not knowing why drives you crazy. I guess it's something that you just have to accept and move on.
So just remember be careful with indifference- it's the most powerful weapon a human being possesses.