Wow. People have listed all sorts of words, phrases, misuses of grammar, etc. that irritate them. Personally, I think some people are overreacting a little bit, but hey, that's their right.
However, when some people say that the use of OMG irritates them, others feel a need to pipe in and say that it isn't OK for them to be irritated. Why can't we leave it alone and accept that some people, for whatever reason, don't enjoy hearing this particular phrase?
I'll get back on the bike soon, I promise!