In most groups or organizations, there appears to be the Haves and the Have-Nots. They could also be referred to as the in-group and the out-group, or any other number of names. The key is that their is a perception that certain members have special privileges that others do not.
Some examples in the mililtary:
Pay
Haves: Officers
Have-Nots: Enlisted
Duties/Details
Haves: Could be Section Sergeant, Officers, etc. Basically, anyone who in the particular group who feels that they do not have to help in the cleaning and other details that everyone else does.
Have-Nots: The people doing the work
Perks
Haves: People who get to travel (instead of being stuck on a FOB), people who get time off, or any other number of things that create inequalities
Have-Nots: Those watching from the outside while others travel, get time off, etc
These differences can cause a great drop in morale for the have-nots, or they can also sometimes be used as a motivator. Any of the Have-Nots should theoretically want to move into a position of the Haves. If there is a clear path for any Have-Not to be able to perform exceptionally and therefore become a Have, it can create a reward system for exemplary work. However, if there does not appear to be any correlation between performance and position, then all that these perceptions do is create distrust, resentment, and frustration.