The ever-encroaching use of "like" instead of "as if" can offend traditionalists, such as in the sentence: "I feel like I'm going to be sick."
Mixing up your modals - "might" and "may" - is another bugbear. As is the grocer's apostrophe, so-called for its frequent appearance in fruit and veg shops advertising apple's, pear's and sundry other green's. "Can I get…?" is for some an offence that should lead shopkeepers to frogmarch the culprit off the premises.
(Sigh) Yes, I hate bad grammar.