Superboy just doesn't know how hot he is. In the Young Justice episode, "Targets", he and Miss Martian as getting ready for their first day of school. When he's told that he can't wear the "S" shirt (which is basically his costume) to school, he just turns it inside out.
He takes it off right in front of Megan, who has the biggest fangirl crush on him. He seems to be oblivious to the fact that he just unintentionally turn Miss M (and the viewing audience?) on.