An expression that I'm coming to dislike quite a bit is "That's sweet." To me, it seems like a very dismissive statement, essentially saying "Isn't that such a nice opinion. Now go along and play now." How bloody rude. If someone is expressing a compliment, "Thank you" is much more appropriate. It says nothing about whether or not the compliment is deserved, but it does acknowledge the person giving the compliment. I've got more to say on this but it hasn't percolated up yet.