Yes, I occasionally morph into a Grammar Nazi.
Most of the time, I try to mind my own business, but when I spot errors in English, I sometimes can’t help myself. I think it’s instinctive. I have been pointing out grammar, punctuation, and sentence structure errors in almost everyone’s writing since I was in high school. Sometimes the people who have erred take offense at my efforts to improve their grammar skills.
Then again, sometimes they find it humorous.
Back in the early 90s, I was traveling home from work (on a bus) one afternoon when I noticed an ad that proclaimed Trade-ins Now Excepted. Those words were posted in large letters on a signboard in front of a mobile home sales lot.
Well, that wasn’t what the-powers-that-be meant to say. At least, I hoped it wasn’t. When I got home, I looked up the phone number of the sales lot, called the business, and spoke to the manager.
I tactfully pointed out the error in the sign, explaining why it was wrong. “I think that’s the opposite of the message you’re trying to send,” I said. “If you are excepting trade-ins, you are not accepting trade-ins.”
The manager chuckled and said he hadn’t noticed the sign because he had nothing to do with setting it up. He also said I made his day by telling him about the mistake.
And, yes, when I rode by the sales lot the next day, the sign had been corrected.
WestWord Arizona 
Ha ha. He laughed, but you did a good deed for that man. This post reminds me of the much publicized controversy over “10 items or less” versus “10 items or fewer” at supermarket chains a few years back.
Stater Bros. supermarkets have signs that read “15 items or fewer.” At least the one near me does. When I remarked that they had used the right word, the cashier looked at me as if I had just announced I was from Mars.
According to Fowler’s Modern English Usage: “Supermarket checkouts are correct when the signs they display read 5 items or less (which refers to a total amount), and are misguidedly pedantic when they read 5 items or fewer (which emphasizes individuality, surely not the intention).”
Five items or less “sounds” more correct than five items or fewer. Hmm. . . . I’ve used the singular verb “sounds” here. So, in this comment, I’ve recognized the phrase as referring to the total amount. However, technically, you can count items one by one. On the other hand, you can also count dollar bills one by one. I don’t think someone would say, “You can buy the widget for five dollars or fewer,” instead of “five dollars or less.” I guess this is one of those grammar rules that is up for debate (future blog post perhaps?). As for the cashier, not to seem politically incorrect, but she probably didn’t understand why I made that remark. I don’t think English is her first language.