Things like whether the period goes inside or outside the closing quotes. (If you follow American-standard rules, it goes inside. For the Brits, outside, or variable.) And even though the placement doesn't change the meaning, some folks are ready to declare war on anyone who doesn't do it the right way—their way.

Same with ensure or insure, imply or infer, and dozens of other options. You can find lots of good dictionaries and style manuals that give the okay to either in certain uses—which is to say they recognize that good writers and speakers sometimes use the less-standard member of the pair. But that doesn't seem to be enough for the so-called purists, who see their jobs as protecting the virginity of our beloved language.

When I see grownups raging at each other over one of these trivial points, it reminds me of Ogden Nash's clever poem about the apotheosis of purists, Professor Twist. Here's the last part:

Camped on a tropic riverside,
One day he missed his loving bride.
She had, the guide informed him later,
Been eaten by an alligator.
Professor Twist could not but smile.
"You mean," he said, "A crocodile."

It would be nice if all members of the grammar gestapo would read that, or maybe even keep it posted where they can see it while they work.