Your Scarlet Letter.
Obviously no one is going to run around sewing letters to people's clothes, but if everyone had to wear a button that stated your worst attribute, your darkest secret...what would it be?
For example, mine would probably say..."only goes after what she can't have, and stupidly pursues it to a fault"
"...you want to be truly unselfish? Love someone or die for someone. Those are the only good deeds you can perform without any hope of personal gain."