knappyhead is looking for a career that will allow him to have money. He doesn't want to work hard, and values social relevance. He enjoys Science and Math, and is good at helping people.
Orin Scrivello, DDS (Little Shop of Horrors) If your teeth are weak, if they fall out, you're screwed; you'd starve to death for sure, and so we have the dental profession, to keep peoples maws chewing proficiently. Orin Scrivello, the sick and twisted demonic dentist, uses his powerful tools for evil.
Dr. Derek Shepherd (Grey's Anatomy) A physician is an unspecialized doctor: They need to know about everything, but only enough to diagnose and refer to another doctor, a specialist. Dr. Derek Shepherd is a general practitioner on Grey's Anatomy.
Hunter 'Patch' Adams (Patch Adams) A pediatrician is a doctor who specializes in child healthcare. I promise you, if you become a pediatrician, there will be much more laughter than there was in that awful Patch Adams.
Dr. Ben Sobel (Analyze This) Psychiatry studies human behavior and the brain, with the intent of helping patients function effectively. Dr. Ben Sobel is a psychiatrist like any other, but he didn't know how to discriminate when choosing clients. Who would treat a mobster?
Alan Harper (Two and a Half Men) Chiropractors are doctors that treat back injuries and other back-related ailments. However, they are often considered quacks that do nothing. After all, Alan Harper, a frontier chiropractor, has nothing better to do all day than deal with Charlie Sheen's comedic antics.