One other interesting point he makes is that a person will be better off at the top of the middle class than at the bottom of the upper class. Being at the bottom of the upper class means you go into a store and you can't afford most things as opposed to at the top of the middle class you can
+1, I always say that most people don't know the right explanation of the word 'afford'. IMO being able to afford something is not merely having the money to buy it but also afford it getting lost, ruined, breaking or whatever. Basically affording something goes far beyond just being able to buy it.
The typical example I give is when a guy has the money to buy a nice and expensive car but get stressed, angry and upset when it gets a little scratch (ex), he can't afford it, period.