I remember reading something like that, but I think it may have been in one of the blogs linked from here.
It was about why people always feel the need to keep up with the Jonses. The argument was that the exponential shape of the income distribution graph means that someone who is 5% below you on the income scale makes almost as much money as you do, but someone who is 5% above you on the scale makes WAY more than you do. And since people tend to only compare themselves by looking up, not down, it looks to them like the rich are always much richer.