YOLO (I really want to know when this became a thing.. I must have been hiding under a rock when this happened).
Using text speak; u, c, 4 etc. It's annoying.
"Epic" mainly my nephew just does this but he says Epic near enough about everything when it had became a thing. Made me hate the word hearing it constantly.
"Kawaii" Instead of saying it in English (Cute/Pretty), there's a lot out there that feel like they're into Japanese stuff so they must mix it up. Seriously, stop. I'm into Japanese stuff too but it's flipping annoying, either speak in Japanese completely when you do it or don't do it at all. I can take it being said as a joke but when you are saying it because that's how you describe things that you find cute.. just stop.