I hate "six of one, half a dozen of the other", and I don't even know why. It just sets my teeth on edge when someone says it.
I also get annoyed by "no worries" but not every time. One person can say it and it's fine, and another person will annoy the crap out of me with it. I'm not clear on what the difference is, but I think it must sound more appropriate in some contexts than others.
When people misuse the word "myself" I want to correct them. It's not "Stan & myself went cow tipping", it's "Stan and I went cow tipping." In response to the question, "Who the hell knocked over that poor cow?" the correct response is not "Stan and myself", it's "Stan and me".
Without a doubt, my most hated phrase is
"I just threw up in my mouth".
It gives me a visual image and honestly makes me feel sick whenever I hear it or read it. See - I even covered it with a spoiler tag so I don't have to read it in my own post.
Just saying, don't use that phrase if you want to stay on my good side.