Everything that has something replaced with an 8 (pl8, l8r), plz, u, thx, and all kinds of stupid abbreviations like that. Lol, btw, omg and stuff like that don't annoy me, but I get so pissed off if someone says "Can u buy my pl8 l8r" or "Thx dude ur the best" (it's a compliment, but anyway). In moments like that I hope that trout barrage really existed. Also! I hate the word noob when it's overused and 'one' being replaced with '1'.