A Marriott rep hung up on me once, about 3 years ago. Apparently he was annoyed with me. I had asked, and he had answered, a question. I was doubting his answer, so rephrased it and asked again a slightly different way. He said "I just told you that!" (which he had of course) and hung up on me.
I work in a customer service department and I have used this as an example of how we do NOT want to do business a few times since then.