The Genius of Dogs
We often think of evolution as being the survival of the fittest, where the strong and the dominant survive and the soft and weak perish. But essentially, far from the survival of the leanest and meanest, the success of dogs comes down to survival of the friendliest.
Most likely, it was wolves that approached us, not the other way around, probably while they were scavenging around garbage dumps on the edge of human settlements. The wolves that were bold but aggressive would have been killed by humans, and so only the ones that were bold and friendly would have been tolerated.
Friendliness caused strange things to happen in the wolves. They started to look different. Domestication gave them splotchy coats, floppy ears, wagging tails. In only several generations, these friendly wolves would have become very distinctive from their more aggressive relatives. But the changes did not just affect their looks. Changes also happened to their psychology. These protodogs evolved the ability to read human gestures.
So, far from a benign human adopting a wolf puppy, it is more likely that a population of wolves adopted us. As the advantages of dog ownership became clear, we were as strongly affected by our relationship with them as they have been by their relationship with us. Dogs may even have been the catalyst for our civilisation.
If you are interested in this subject, The Genius of Dogs published by Dutton is a good read.