Why are dogs and cats the most popular pets?

I'm with tajnz. I think it has to do with how long dogs and cats have been with us. People have used dogs for hunting and protection forever, and cats have been helping people control mice. We also can't forget cats and ancient Egypt!

A lot of people don't realize how much other animals can interact and bond with their humans. I often run into people who are shocked that I actually take my bird to the vet. They just don't think of birds as "real pets." :/