My introverted son absolutely loved the cold-calling position he had. It was for one of those charity/kinda not organizations that gives a teensy portion back to the charity, but he didn't realize it at the time. He was 16.

Because he can mimic any, and I mean any, accent, he pretended to be all different kinds of people ... He made it fun for him. (I'm fairly certain he'd not last a day at that kind of job now. :)