One infuriatingly common grammar mistake involves the apostrophe.

Apostrophes have only two purposes in English: possessives (e.g., John’s watch) and contractions (e.g. you’re, it’s). Apostrophes don’t indicate plurals.

Tuesdays should only have an apostrophe if Tuesday is someone’s name and you’re talking about Tuesday’s new sweater. You know, that she thing wore to the office on Ugly Christmas Sweater Day. Quite frankly, other than Tuesday Weld, we are hard-pressed to think of another Tuesday to which we can apply this rule. Perhaps we should move on to Wednesday of Addam’s Family fame, or Sergeant Friday of Dragnet. Wandered into the weeds a bit on this one, didn’t we?

One curious misuse of the apostrophe is when referring to all members of one’s family. For example, if you don’t want to list each Johnson family member’s name and instead refer to them as a group, you would write “the Johnsons,” not “the Johnson’s”.

Another very common mistake is to put an apostrophe in a decade: the 1980s was a decade, the 1980’s was not! We are hurting ourselves trying to figure out exactly what the 1980’s was in any case.