If person x always wants to/is ready to hang out with person y, person y may soon wonder why person x doesn’t have better things to do. They could hang out with

If person x always wants to/is ready to hang out with person y, person y may soon wonder why person x doesn’t have better things to do. They could hang out with other people, cultivate hobbies, do work, etc. The continual choosing of hanging out with person y almost suggests that person x is dull. People don’t think this way about dogs (maybe they do about cats). The human-dog relationship is also well-defined. Play, feed, house, take for walks. Your dog is not suddenly going to ask for a romantic relationship or con you into loaning them money. Closeness is just less risky.