One of the major issues that has divided people throughout recorded human history is precisely the matter of division - more specifically, how scarce resources ought to be divided. A number of different principles have been proposed, including: everyone should get precisely the same share, people should receive a share according to their needs, and people should receive a share according to how much effort they put in. None of those principles tend to be universally satisfying. The first two open the door wide for free-riders who are happy to take the benefits of others' work while contributing none of their own; the third option helps to curb the cheaters, but also leaves those who simply encounter bad luck on their own. Which principles people will tend to use to justify their stance on a matter will no doubt vary across contexts.
If you really wanted toys - or a bed - perhaps you should have done a little more to earn them. Damn entitled kids...
The latter two options also open the door for active deception. If I can convince you that I worked particularly hard - perhaps a bit harder than I actually worked - then the amount I deserve goes up. This tendency to make oneself appear more valuable than one actually is is widespread, and one good example is that about 90% of college professors rate themselves above average in teaching ability. When I was collecting data on women's perceptions of how attractive they thought they were, from 0 to 9, I don't think I got a single rating below a 6 from over 40 people, though I did get many 8s and 9s. It's flattering to think my research attracts so many beauties, and it certainly bodes well for my future hook-up prospects (once all these women realize how good looking and talented I keep telling myself I am, at any rate).
An alternative, though not mutually exclusive, path to getting more would be to convince others that your need is particularly great. If the marginal benefits of resources flowing to me are greater than the benefits of those same resources going to you, I have a better case for deserving them. Giving a millionaire another hundred dollars probably won't have much of an effect on their bottom line, but that hundred dollars could mean the difference between eating or not for some people. Understanding this strategy allows one to also understand why people working to change society in some way never use the motto, "Things are pretty good right now, but maybe they could be better".
Their views on societal issues are basically the opposite of their views on pizza
This brings us to the science (Xiao & Bicchieri, 2010). Today, we'll be playing a trust game. In this game, player A is given an option: he can end the game and both players will walk away with 40 points, or he can trust and give 10 points to player B, which then gets multiplied by three, meaning player B now has 70 points. At this time, player B is given the option of transferring some of their points back to player A. In order for player A to break even, B needs to send back 10 points; anymore than 10 and player A profits. This is a classic dilemma faced by anyone extending a favor to a friend: you suffer an initial cost by helping someone out, and you need to trust your friend will pay you back by being kind to you later, hopefully with some interest.
Slightly more than half of the time (55%), player B gave 10 points or more back to player A, which also means that about half the time player B also took the reward and ran, leaving player A slightly poorer and a little more bitter. Now, here comes the manipulation: a second group played the same game, but this time the payoffs were different. In this group, if player A didn't trust player B and ended the game, they walk away with 80 points and B leaves with 40. If player A did trust, that meant they both now have 70 points; it also meant that if player B transferred any points back to player A, he would be putting himself at a relative disadvantage in terms of points.
In this second group, player B ended up giving back 10 or more points only 26% of the time. Apparently, repaying a favor isn't that important when the person you're repaying it to would be richer than you because of it. It would seem that fat cats don't get too much credit tossed their way, even if they behave in an identical fashion towards someone else. Interestingly, however, many player As understood this would happen; in fact, 61% of them expected to get nothing back in this condition (compared to 23% expecting nothing back in the first condition).
"Thanks for all the money. I would pay you back, it's just that I kind of deserved it in the first place."
That inequality seemed to do two things: the first is that it appeared to create a sense of entitlement on the behalf of the receiver that negated most of the desire for reciprocity. The second thing that happened is that the mindset of the people handing over the money changed; they fully expected to get nothing back, meaning many of these donations appeared to look more like charity, rather than a favor.
Varying different aspects of these games allows researchers to tap different areas of human psychology, and it's important to keep that in mind when interpreting the results of these studies. In your classic dictator game, when receivers are allowed to write messages to the dictators to express their feelings about the split, grossly uneven splits are met with negative messages about 44% of the time (Xiao & Houser, 2009). However, in these conditions, receivers are passive, so what they get looks more like charity. When receivers have some negotiating power, like in an ultimatum game, they respond to unfair offers quite differently, with uneven splits being met by negative messages 79% of the time (Xiao & Houser, 2005). It would seem that giving someone some power also spikes their sense of entitlement; they're bargaining now, not getting a handout, and when they're bargaining they're likely to over-emphasize their need and their value to get more.
Resources: Xiao, E. & Houser, D. (2005). Emotion expression in human punishment behavior. Proceedings of the Nation Academy of Sciences of the United States of America, 102, 7398-7401
Xiao, E. & Houser, D. (2009). Avoiding the sharp tongue: Anticipated written messages promote fair economic exchange. Journal of Economic Psychology, 30, 393-404
Xiao, E., & Houser, D. (2010). When equality trumps reciprocity. Journal of Economic Psychology, 31, 456-470