The pursuit of huge amounts of wealth. I can never imagine why someone worth hundreds of millions of dollars won't rest until they get more. And they do it until the day they die. I'm just not wired like that. The closest thing I have heard as an explanation to the seeking of crazy wealth that they could never spend in ten lifetimes is when I heard Bill Gates say in an interview that it's not so much the money, it's just a way of keeping score. Which is a sick idea when they can see people every day that are struggling for food and shelter.
Now I don't think Bill Gates is one of the above mentioned bad actors. He has in his later years become somewhat philanthropic. But anyone seeking obscene wealth for the power it brings, is a weak person indeed.