I've sometimes been noted to get excited or angered over little things that don't really matter, and today I found myself in one of these times. A chef on TV was cooking a chocolate cake with ricotta in it. Each time she said, ricotta, though, she'd revert to the Italian pronunciation. For half a second, she went from fine English to Italian and back again. I'm not sure why it annoys me, but really, if you're going to say a single damned word, why even bother changing the accent if all it does is make you look pretentious? Not to mention, it disrupts the flow of what she's trying to say. I recalled at least five occasions where she was stringing moderate-length sentences together and wedged into the middle of them the accented ricotta, thereby disrupting in an almost jarring manner what she had going.
TL;DR, people speaking a single word with a distinct accent in a sentence of otherwise plain English really does annoy me, even though I may only see it happen on average about once a month.
What are some other non-important things that you see, that despite their irrelevancy, still manage to annoy you?