This bugs the heck out of me too to the point where I'm always a jerk about it and responding with, "So you care then," and always getting a confused reply in return. While on the subject of grammar, my other two huge pet peeves are people incorrectly using "good" instead of "well" and "borrow" instead of "lend." No, I can't borrow you a dollar, I'd be willing to lend you one if you could actually ask me correctly.