because humans are social mammals, they need to understand their own behaviours

because humans are social mammals, humans follow certain behaviours, 

those behaviours can be divided from other behaviours, analyzed and understood 

because humans are social mammals, humans wants each others trust to if need be, cooperate with each other 

modern version of cooperation is family, work, baby sitting, repairing home and so on 

this creates the need of a reputation of every human in the social group and the human social group is of course the entire human population on this planet because of tv and radio media and internet connected media 

because of this human men feels a need to prove that they are loyal to work, which likely entails being loyal to the social group, which in this case is the company and possibly collegues/friends

and human women feels a need to prove that they are loyal to a family, which likely entails being loyal to the social group which is not only boyfriend/husband, but also relatives and friends 

these behaviours are so obvious that noone discusses it or even seriously thinks about it, 

but these behaviours might have consequences for the individual human 

a human man might be reluctant to do things that might damage his reputation among his social group: companies where he works or companies where he might work in the future, collegues/friends

this might lead to that a human man does not do what he wants in life, 

he does not fulfill his dreams 

a human woman might be reluctant to do things that might damage her reputation among her social group: boyfriend/husband or future boyfriend/husband, friends and relatives, 

this might lead to that human woman does not do what she wants in life, 

she does not fulfill her dreams