Fairness lies in treating like cases alike and unlike cases unlike. A teacher that awards A-students with a star yet provides no star for lesser grade earning students is not treating lesser grade earners unfairly. In this case, not giving an A-student an earned star to a student who earns an ‘A’ is unfair to that student, and awarding a star to a lesser grade earner is unfair to all the students, especially the ‘A’ students.
If the teacher decides to award a star to a B-student but does so for a different reason (oh say, biggest improvement), then we need to be mindful of my first sentence: fairness has to do with like and unlike cases. In this scenario, there’s a special case (which is greatest improvement vs not greatest improvement). So long as the B student receives the star because of belonging to that case, that is not unfair to other students—even the A-students.
As to your “like crap” response, the group pertains to all workers. It would be unfair to treat one good. It would be right, but it would be unfair.
People too closely associate some forms of immoral behavior as being unfair. I’m just saying there is a difference worthy of being mindful of.