We used to have a saying on the copy desk: Don't follow the stylebook out the window. In other words, common sense should govern which style rules you enforce.
The Associated Press Stylebook is the guide we use for deciding how to handle some usage matters. We follow it -- mostly. Some of us love it, and some of us hate it. Some of us see it as a blunt instrument we can use to subdue crazed writers. And some folks see it as a rich source for parody. Those are the people behind the Fake AP Stylebook on Twitter. Warning: They use words that are decidedly not in the AP Stylebook but which can be heard from time to time in certain workplaces.