I think no such thing. I only used that in comparison to another low paying profession like teaching, where the motivations of those who commit their lives to it are not entirely selfish. Not all, but many teachers who slug it out in schools for 30 or more years feel it's their duty to serve society by improving the minds of our nations children. There are other professions with similar individuals, Law (pro-bono, non-profit, and government service work), medical (similar to law), missionary work (here is a different breed of pilot), police, military etc.... They may love their job, but it's the product of their work that they derive their primary satisfaction from.