Temperament is affected by a number of factors, including heredity, training, and socialization. Puppies with nice temperaments are curious and playful, willing to approach people and be held by them. Choose the middle-of-the-road puppy, not the one who's beating up his litter mates or the one who's hiding in the corner. Always meet at least one of the parents-usually the mother is the one who's available-to ensure that they have nice temperaments that you're comfortable with. Meeting siblings or other relatives of the parents is also helpful for evaluating what a puppy will be like when he grows up.