Please people, if a flower can get the rules right so can you. Dave Barry may have confused you but, though the apostrophe’s history is long, punctuation really is not as difficult as it may look. You can be right 99% (ok, but at least 90%) of the time by only using an apostrophe in three simple cases:
- To indicate possession (I drove Henry’s car. (but not when using one of the possessive pronouns: his, hers, ours, or its));
- To indicate the omission of one or more letters (You’re welcome.); and
- When writing plural letters (watch your p’s and q’s) or plural years (the 1900’s).
Never put an apostrophe before the “s” in a word you just want to make plural. “I saw two cow’s this morning” is just wrong.
I’ve (contraction) read many of Tom Clancy’s (possessive) books (plural), most as they were first published in the 1980’s and 1990’s (plural years).
[later: I’ll give you that the “years” part of rule #3 is optional. References seem split, one showing both “the 1980’s” and “the 1980s” as proper. If you’re going to shorten it by dropping the first two digits (Y2K, anyone?), you would of course replace the dropped digits. “I was born in the ’60s” does indeed appear correct. The main point of my rant, however, stands. No apostrophe should be added to a non-posessive plural.]