I think with some people it's down to jealousy, resentment, or purely because the person/s are seen to be flashing the cash.
I have neighbours who are on benefits and have a mobility car. they are out shopping everyday and come back with loads of shopping. (food/furniture/electrical/etc)
they do think highly of themselves, and that kind of attitude is the kind of attitude that will and does attract the resentment.
I suppose if they were to just act poor it would take some of the attention away
