Alcohol. Doesn't matter what age but people under 25 are the worst. I honestly don't care if your life revolves around alcohol. That your life has no meaning without it, where you wound up waking up or with whom some random weekend. I don't care what you mix with it or if you put Coke in it, or if you choked on your own vomit.
WWE. I hate wrestling. Wrestling is fake. Even the CEO is fake.
God(s) I don't care which fairytale religion you believe in, God isn't going to help you no matter how much you pray. If you prayed that God spare you during Hurricane Sandy, it meant one of your neighbors was going to get hit worse than you. Sucks to be them I guess. If you root for a sports team and you lose, then God must have liked the other team's God prayers a lot better.
Homeopathy, psychics, doomsday, UFOs, etc. If it's pseudoscience or supernatural then I really could care less. I nod and go into happy place mode or leave.