As an English major, and a grammar freak, I'm totally with you. The one that bothers me the most is when people mistake "your" and "you're". If you're not sure, just say the whole thing rather than the contraction. Its not "your stupid." Its "you are stupid." Hence, "you're."
Actually, I had a little funny list of grammar rules in my sig here once, and I got jumped on by everyone. They said they felt offended and whatnot.Sorry, it's not my fault you can't understand elementary English rules, and its definitely not my fault that you feel the need to put down everyone who does.