I realize that this is barely a diary, and also that some may take issue with expirements done on animals, but this is a facinating (and very funny) look at what happens when inequality is presented in the animal world.
This is an excerpt from a TEDtalk given by Frans de Waal, who shows an expirement where two monkeys are each given cucumber slices for performing the same task, and then one monkey gets "upgraded" to receiving grapes for performing the task.
Even monkeys agree, pay inequality sucks!