Does the direction a dog wags his tail have anything to do with how much he loves you? It could be. 🙂 This article from the New York Times says that if a dog’s tail wags more to the right side of his rump, he feels something very positive. Not quite as much so if his tail is wagging to the left side of his rump.
This study was done in Italy, at the University of Trieste. It is quite an interesting read.
I personally know that some dogs, like people, are either left-handed or right-handed. Lucy is our only dog who will shake, every single time, with her left paw. All the other three shake with their right paws. Though this study is based more off a right/left brain response than being right or left handed. I thought it was interesting!