Life is not fair. I dare anyone to tell me they have always been treated fairly or received everything due them. To expect life to treat you with fairness is comparable to thinking all your questions will be answered at the end of the yellow brick road. Thinking so can be a pit of despair, a trap you set for yourself.
Like everyone has, I had the experience (in my mind) of being treated unfairly in a previous job. Although highly qualified and rated as such for a promotion to a new position, the position went to someone else with much less seniority. I was at a disadvantage for other perceived needs of the organization. I wasn't happy about it but I understood it wasn't personal. A couple of years later, I lost out on a promotion to a guy who ride-shared to work with the selecting official. That one really hurt.
If I had said their decisions weren't fair, I would have come across as childish, a complainer, and put the decision-makers on the defensive, making things worse. I soon decided to look for and received a promotion to another organization because what's really unfair is feeling sorry for yourself and not taking charge of your life.
It's unfair to be in the wrong place at the wrong time. It's unfair to have a lower IQ than your brother. It's unfair when you have diabetes or worse. Often, there are those who blame God for being unfair. I recall a story in the Bible where I thought God acted unfairly, as if I could be so bold.
In 2 Samuel 6:7, Uzzah put out his hand to stabilize the ark of God (Ark of the Covenant) when the oxen carrying it stumbled. For this he was struck dead, for God had warned that touching the ark of God was forbidden. To many, Uzzah was was punished in an unduly harsh way, for while he did defy a rule of God, he seemingly did so to steady it as a reaction to help. God's law was upheld, else His will may be doubted. Fairness was not in the equation.
The Lesson
First of all, we are often the worst person to judge fairness when we are affected. Secondly, we can't control fairness except when it come to us being fair to others. That's the lesson! Life is not fair, but each of us can contribute to lessen that fact. And, I believe, when you are fair to others, you will tend to be treated fairly by others.