It's a fine line though.... nearly all of us break grammatical rules of English to avoid sounding like a prat LOL

For example... most of us don't use the word "whom" we just use "who" instead even though "who" is meant to be reserved for a question. Most of us would say "who were you refering to?" instead "of whom were you refering?"

Ending sentences with prepositions! There are only a few that really drive me batty, "but" being a major one.
"Claire's dancing was good but." ARGH! Seriously want to scream every time.