For someone to come to you, and ask you, to sign a piece of paper, article of clothing or body part, means that they hold you, in the highest regard. You can tell them are a pest, superstar or just somebody special and they will hold on to that forever. You can treat them like a loyal fan, groupie of a business contact. Whatever you do, it will, mean more to them than what an average person can say or do. That's power!
Signing an autograph is a moment to use your great power. Use it well.