Unfortunately, I have been cursed with Grammar Nazi Syndrome. The constant need to correct grammar mistakes is both a gift, and a burden. For those who are not cursed the way I am, here is a list of things you should never ever do in the presence of a Grammar Nazi.
1. Pronounce Etcetera like "ecksetra"
A common, yet extremely annoying mistake.
2. Refer to Daylight Saving Time as "Daylight Saving's Time"
It doesn't seem like a big deal, but it totally is.
3. Pronounce Alzheimer's as "All-timer's"
I'm sorry, but exactly where did you find a "T" in that word?
4. Say "could of" when it's actually "could have"
This one is my personal favorite. "Of" is not a verb, it's a preposition. Saying "could of" is basically the equivalent of saying "could under, could in, could beside."
6. Use "good" when you should use "well"
It takes a lot of restraint not to scream when I hear someone say, "You did good."
5. "Valentime's" Day
Simply, what? I have heard grown adults say Valentime's Day. Unless you have some strange speech impediment that turns your N's into M's, please say Valentine's Day.