I think a part of it is jealousy, which is a normal part of human nature. If you see your friend with a new expensive item of clothing perhaps you get jealous. If you see your friend with a new attractive girlfriend perhaps you get jealous, and it's the same with schooling. I went to a state school and in a past life I was a touch jealous of people that went to private school because I wanted it as well. I wanted the connections, the status, and everything that came with that.
But I guess when I got to university, I realised that people aren't defined by their school. I'd made it to the same university as people that went to some of the 'top' private schools in the country and you realise for most part they are just normal people as well trying to do well for themselves who perhaps had a bit of a head start. That would be my analysis.