When your furry friend sees you walk through the door, he or she is usually wagging their tail in excitement. There is no one in the world who is happier that you’re finally home even if you left the house for five minutes. Sometimes when your dog wags its tail it could mean something is wrong. According to Italian researchers, dogs that wag their tails slightly to the right when they are happy to see something and to the left when they are intimidated. Pay special attention especially when your pet meets another dog. They could be telling you that this is not a friend they want to have in their lives.