A double negative is a no-no. – Author unknown

The rules of punctuation seem arbitrary. How can they not, when an apostrophe looks like nothing in this world so much as a comma that can’t keep its feet on the ground? Or when, by simply placing next to that wafting comma its twin, one creates (of all things) a quotation mark? – Richard Lederer and John Shore, Comma Sense: A Fun-damental Guide to Punctuation

Linguists are no different from any other people who spend more than nineteen hours a day pondering the complexities of grammar and its relationship to practically everything else in order to prove that language is so inordinately complicated that it is impossible in principle for people to talk. – Ronald W. Langacker (b.1942), Language and Its Structure, 1973

I always put the apostrophe in “ain’t” to make certain I’m using proper improper English. – Author unknown