I think one of the problems of wealth distribution and attitudes about it in the U.S. is that it does shoot up so rapidly in the upper 1%. We're a very upward-looking society so it's easy for someone making $250K a year to say "I'm not rich, I still have a mortgage, I have to work for a living I can't just spend whatever I want, whenever I want -- I know there are people further up the latter than me who have so much more money, I must be middle class."

Absolute percentiles are useful because they do show you where you stand in relation to the rest of society. Families making $250K may not be Scrooge McDuck-style super-rich, but they're indisputably in the top few percent of the nation in terms of income. It's hard for those folks to claim to be middle class when 90+ percent of their fellow citizens make less.

It's also worth noting that people's lifestyles and "necessities" expand to fit their income, particularly if their income goes up relatively gradually. I've literally heard people say, "Well, I make $400K a year but I'm not rich because it costs a lot of money to pay mortgage and taxes in Westchester County and send my kids to private school and drive a nice car." They think that "rich" means "disposable income I can spend a whim," when in fact living in Westchester and sending the kids to private school is part of being rich.