What makes someone a "wonderful houseguest"?

During the power outage, I stayed at a few different friends’ houses. They all mentioned to me afterward that I was a wonderful and understanding guest. I know I tried very hard to be considerate, helpful and undemanding. I also tried to respect each family’s own routines and privacy and not get in the way of their need for downtime. I’m just wondering what, in your opinion, makes someone staying with you a great guest.