Dogs bring us things, therefore adding decorative tooth-marks to items like slippers and the newspaper. Dogs alert us to the presence of nasty things in our yard. Dogs are always there for us. Dogs help us budget our money. Dogs help us eat a healthier, tastier diet.
Dogs are always desperate to play and are a perfect vehicle for exercising.
See previous point about exercise. One reason many people overeat is to comfort themselves. Next time you inappropriately get the munchies, do an experiment. Talk to, pet or play with your dog instead. The resulting endorphin high may be a satisfactory substitute, helping to control those unhealthy eating urges.