I think being offended by a compliment is a little much. When people are just being nice, and maybe being awkward in the process because it makes them nervous, I see it as a nice gesture and appreciate their effort and sometimes their courage (probably took guts). I get what Thena and Thump are saying, though. Some people may feel a certain way. Like this: a dude might tell me he thinks I'm pretty. My answer will maybe be something like an awwww thanks. Lol But if a person paid attention to my response in class or at work or whatever, and complimented my insight, asking another question perhaps so they can jump in... I might be more intrigued or interested than just "awww". So while a compliment about looks can be appreciated as sweet and maybe even ballsy, interest in me as a person with a brain can be more effective.
"Hipster is what happens when young hot people do what old ladies do." -Exian