"Fairness" is a word your parents use against your smarter brother, in order to give you a share of what he has, so you can get what you want. Your parents use this word to either skip teaching you how to get things by yourself or to avoid telling you a cold truth: you will never get what you want because you are helpless.
Nowadays, fairness is an artificial construct so engrained in this childminded/victimized society, that you can use it as a joker to get what you want.
Be careful, using fairness, as a shortcut to get what you want, can prove useful many times, but it does so at the expense of becoming lazy.
Make sure you always know other ways to get what you want, and use fairness as a quick shortcut only.
Democracy is a result of lack of education or lack of serving cold truths.