Therapy dogs come in all sizes and breeds. The most important characteristic of a therapy dog is its temperament. A good therapy dog must be friendly, patient, confident, at ease in all situations, and gentle. Therapy dogs must enjoy human contact and be content to be petted and handled, sometimes clumsily.
A therapy dog's primary job is to allow unfamiliar people to make physical contact with it and to enjoy that contact. Children in particular enjoy hugging animals; adults usually enjoy simply petting the dog. The dog might need to be lifted onto, or climb onto, an invalid's lap or bed and sit or lie comfortably there. Many dogs contribute to the visiting experience by performing small tricks for their audiences or by playing carefully structured games.