By making wealth into a dirty word, people started to believe it was, in fact, dirty.
So en masse we engraved this into our subconscious: Wealth is dirty, and I don't deserve to have it. When one believes this, especially when it's been taught like this: more or less from generation to generation, because the rich are bad, a humble slave who works for a wage is good, it surely generates an impact.

Lucky for me, I've always believed that wealth is within my reach, that I am deserving of it, and that good things can be done with it. Call it karma, or whatever. This positive attitude helps. If you do it the other way around, and believe you don't deserve it, or that it doesn't have a place in your life, well then the opposite happens.