I’m not certain if this is what you were getting at, but these are mine:
An historical - It doesn’t follow the general way of using a or an with consonants and vowels. Nor does it change the meaning if I said a historical (event) instead an historical (event).
Fewer and less. I understand that there is a rule, but the rule is fucking dumb. If I say there are less people or if I say there are fewer people - the end result is the same that there isn’t as much as there was before.
Language is fluid. As long as we understand the meaning of what is being said then who cares?