Temperament, which, ironically, isn’t always easy to see. To shed some light on the subject, enlist the help of an adoption counselor at the shelter, or hire a trainer to go with you to assess the dogs you’re considering adopting. Ultimately (especially for families with children) what you’re looking for is a friendly, happy, outgoing, dog who can’t get enough of you petting him or her. Making friendly eye contact with you is a big plus, too. When properly evaluated, this type of dog can be less at risk for aggression issues, because a dog who asks you for physical contact is going to be much more likely to be ok when you have to handle him in a way he wishes you wouldn’t (ear cleaning, nail clipping, etc), than one who doesn’t enjoy or seek pleasant physical interaction.
Remember, too, that temperament is genetic! As with people, so, to some extent, is it with dogs. They are who they are. Your mom probably had this talk with you at some point when you were dating someone you were incompatible with. The old expression “You can’t ask a tiger to change his stripes.” comes to mind.
It’s imperative that you remember this lesson during your dog/puppy search. If your dream dog is a snuggle bug, then when you’re told by an adoption counselor or trainer that the puppy you’re considering is independent – i.e., likes to play by himself, is off wandering around the room, thinks a squeaky toy is more fun than any human he’s ever met – DO NOT think to yourself “That’s fine. When I take him home he’ll see how much fun I am and what great games we can play and he’ll become bonded to me.” Maybe. But more likely not. Remember the tiger.