As you know, I have experienced this with a few friends too, and been affected by it myself.

My feeling on it probably needs to be explored a little further, but I personally believe that money is a tool, nothing more. It can be used in many different ways, and it's how people choose to use it that determines their character, not the amount they have.

When I think of all this I think of a friend of mine and a conversation we had last year. Because of her personal set of beliefs, it was if she purposely avoided career paths that would excel her financially because she had moral opposition to having a well-paying job. She wanted to do jobs that would do other people good, but not make her wealthy at the same time. Then it was pointed out to her that if she found a job where she could both do good, and make gobs of money (which would be possible with the career she was interested in), then she could do multiple times more good for others with that. It was like she never had seen it that way. Just saw "Money is Bad."

Back to me. I think to a degree we use money as a way to keep score of our personal success. Ultimately, that's rediculous, but we do it anyhow. However, given the free market we live in offers gobs of ways to show off your money just for this reason, (even if it means going into extreme debt), this is totally reinforced. It's a tough current to navigate, and at some point we all get a touch of "keepin' up with the Jone's." I don't think I have a bad case of it, but I certainly feel shame at times for what I can't show in my bank account. But I reassure myself knowing that I am steadily building my personal dollar worth as time goes by, with a plan in place to help when I need it. And, it's also about giving the finger to those that see me driving my fully-paid-for 98 Honda Civic, while in their H2 looking down their noses at me. Screw them! Luxury cars are insanely bad investments, and it just tells me how dumb they are about money.

Personally, having money is not something I think a person needs to feel any shame over. Money itself is just an object and a tool. How you get it and how you use it can be something to be ashamed of or it can be something to be proud of. As my wife and I are both surgeons, we have a fair amount of money. I am not ashamed of that, but this may be due to the fact that 1.) Counting college, medical school, and residency I've invested 15 years of my life just to get to the point where I am now - and residency consisted of working 80-120 hours per week, little or no sleep every third night, and a total of 5 or 6 weekends off in a 5 year period. 2.) I have a personally rewarding job and I get to make a significant impact on other people's lives (for the better I hope) on a daily basis. 3.) I do not have to worry about ever being able to provide for my family and I don't have to worry about having money after I retire.
I could go into more detail, but I'm not trying to brag. I am just trying to emphasize my point that how you earn the money and how you spend/invest it is what matters. Unfortunately those people who don't earn their money or those who steal it, and those who accumulate money for the sake of getting more money probably don't feel any shame about it, even if they should (Paris Hilton, the Enron crew, etc). If you do feel shame over having money, I doubt it is just the money itself that is the source of the shame. I am comfotable with how I've gotten my money and how I am using it, so I don't feel ashamed at all.