In an episode of Seinfeld, Elaine was dating a man because she wanted to be dating a doctor. She then finds out that he never managed to pass his licensing exams and therefore couldn't yet practice medicine. After she helps him pass, he dumps her, saying this:

Ben: I'm sorry, Elaine. I always knew that after I became a doctor, I would dump whoever I was with and find someone better. That's the dream of becoming a doctor.

Which illustrates the point rather nicely.