The dog or cat that shares your home is not, in any interesting sense, simply your pet — you are each other's companions, shaped by each other's routines, alert to each other's moods, conducting a wordless dialogue that predates human speech by several million years. Nasreddin's donkey knew when he was in trouble long before he did, which is either the advantage of a companion or a critique of his own self-awareness. The examined relationship with an animal is often more honest than many relationships with people.
Each step builds on the last.