What motivate a person to work? There is plenty of study that has asked this question and tried to quantify how much it is for money, a feeling of being useful, the social environment, perks, having fun, social status gain, and so on.

Pretty sure more males harbour a secret desire to be a nurse than males that harbour a secret desire to be a garbage man, and yet we see nurses are 90% female and garbage men being 90% male. The question is why.