If we, as a species, never learned to domesticate the dog then we may not even be alive today. Many millenia ago the population of homo-sapiens was wearing thin and when our agriculture began, Dogs were domesticated and used to assist with the agriculture. They could be used for herding, hunting and guarding. Because of Dogs humans were able to flourish at the time and survive as a species.

Where were the cats? Ok, they hadn't evolved and been domesticated in their current form for another few thousand years yet but you couldn't get a cat to do any of that.