I get what you're saying but, from personal experience, not really the case. I grew up in a town in Fairfield County Connecticut. Its one of the wealthiest towns in the country. My parents both grew up below the poverty line and made their fortunes when they were young - like, early 20s, and it never changed their personalities. We were brought up in a super modest household, and honestly sometimes they'd go out to the theater or whatever rich people stuff rich people do, and they'd be asked "what are you doing here?" Like my parents lived so modestly that flashy rich people couldn't believe they'd be able to afford theater tickets because they drove a 2002 Volvo station wagon.

Anyway, since I was 15 I've worked in fine dining in Connecticut, New York, and Denver. I still deal with rich assholes all the time. If I engage with my tables enough I can usually get a feel for whether they're nouveau riche, old money, or just run of the mill middle class to just scrapin' by and treating themselves.

Across the board, new and old money can be beyond gracious or beyond dicks. Some people, rich or poor, just suck. Some people are awesome. It's the way she goes. I'd be more inclined to agree that money kind of heightens peoples personalities. If someone is, as a rule of thumb, gracious and kind, they extend that behavior just a bit more because, well they can tip super fat on that pricey bottle of wine. If someone is a douche, they'll let you know any way they can.