A sense of fairness is important. It's not just a social construct either: chimps know when they are being ripped off and they respond with anger.

Why do we have an instinct for fairness when the world is unfair?
Tricky question.

PS:

I think what I'm trying to say is, it is too glib to respond with "Life is not fair".
Fairness is an idea that needs to be explored, not dismissed.