A few summers ago I took a trip to East Africa. While I was there I saw literally hundreds of elephants, and I can assure you that elephants can indeed look very happy.
Having seen elephants and lions and giraffes and so on in the wild, even going to the San Diego Wild Animal Park (where the animals have room to roam and are treated very well) is rather disturbing.
I haven't gone to a circus in many years, and I doubt I would go to one again.