My biggest beef is with word misuse or people using words they don't understand the meaning of. Pronunciation is easily the most forgivable, sometimes you've only read the word. People using five dollar words wrong to seem smart really grinds my gears when they constantly invert the subject and object of a sentence. Like if they want to say a customer is substituting olives for onions as an example they'll always send it as sub onions for olives, it's easy to figure out cause one ingredient is standard and the other isn't but don't do that while using language you vaguely really from high school.