Rest assured, I am aware that my grammar is not perfect. Sometimes I make mistakes in haste. Sometimes--though I tremble a little to admit this--I know the proper usage and reject it. For example, I use the word "can" when I should say "may". Every time I do, I hear a taunting little grade-school voice in my head saying, "I don't know...CAN you?", but I do it anyway because "may" sounds so prim and 1950s Miss Manners to me that I just can't bring myself to use it. It's as if my whole paragraph will freeze up, cloak itself in a crisply ironed dress, and start vacuuming the living room in pearls and high-heeled shoes.
Still, I identified with Lynne Truss and fully understood her need to carry spare apostrophes.
There are, really, only two schools of thought about this issue: "Grammar as Religion" and "Oh, Lighten Up--Don't NITPICK"
I'm a nitpicker, and I'm here to tell you, it can't be helped.
Sometimes we can suppress the urge to comment out loud, although if there's another nitpicker in the room it's hard to resist a quick, shared, significant look (a la Charlie's Angels), but we can't help noticing. No, really. I don't mean, "I couldn't help noticing that you've included an apostrophe in 'car's' even though you clearly intended the plural and not the possessive," but we REALLY CAN'T HELP NOTICING.
We don't look for grammatical errors. We don't analyze text. They stand out as if they were a thousand feet tall and flashing neon, surrounded by fireworks...and not just any fireworks, but ARROWS pointing directly to the word or phrase in question.
Twice a month, an email goes out to everyone in my office, and it says, "Paychecks are ready, if your hours are complete."
Twice a month, I think, "Well, no. They're ready whether or not our hours are complete--you just won't give them to us unless our hours are complete."
I like the woman who writes the email. She's nice and she's professional and she seems quite intelligent. She's very pretty, too. I don't WANT to criticize her emails over a little technical point like that "if", and I don't do it out loud. But I can't read that sentence without noting that it's not factually accurate. It doesn't express what she meant. It COULD be factually accurate, but it's not; I know that all of the checks are ready. And so my brain issues the correction, every time. And it's every bit as annoying to me as it looks from the outside, but no more avoidable. Less, in fact, because the vast majority of those observations are never spoken.