Everyone makes typos sometimes. The odd apostrophe mistake is not a catastrophe. What I'm talking about is the kind of cluelessness that also pisses Lynne Truss off.
For example, here are some simple fucking rules:
1) The word "yours" NEVER needs an apostrophe.
I mean, think about it. Are you a bloody idiot or what? The word "yours" is in exactly the same category as the word "mine". You don't need to be a grammarian to suss that one out. Where the hell are you going to put an apostrophe in that? Min'e? What's that - mince? Mine'? M'ine? Mi'ne? What the hell are you doing? FFS.
2) "It's" and "its" are two different goddamn motherfucking words, goddamnbuggerybeckettit.
e.g. Your mistake, my mistake, his mistake, her mistake, its mistake.
it's = it is
e.g. It's all one big motherfucking load of shit.
Look at your writing. Can you replace the "it's" you have written with the two words "it is"? If not, delete the apostrophe. Gumhead.
3) If it's a plural, just stick an "s" on the end; it doesn't need a bloody apostrophe.
Anne's top tip for the functionally illiterate: if you're not sure, just miss out the apostrophe anyway. Most people's mistake is too use them too much. To me at least, a missing apostrophe is annoying in the way that a friend owing you a fiver who doesn't turn up to the pub is annoying, but a big, fat, juicy, stinking apostophe where one shouldn't be is like coming home from a hard day at work to find a turd on your pillow. Much more annoying.
Here endeth the lesson.
Oh, and a big cheery hello to slu if he's still stalking me this week. *waves*