No, my Chi is a very loving dog. Toy breeds develop fear aggression when owners nurture fears - picking them up and comforting them rather than encouraging independence and social interaction.
No the boxer, pitbull, dalmatian, chow, and doberman pinschers are more agressive to name a few breeds. Chihuahua may be the smallest dog in the world but not the meanest.
Although some dog breeds have a more predisposed genetic makeup to be aggressive, most often a dog's aggression is the result of the owner's training/lack of training.
