My friends have two boxers, and they are my favorite dogs in the world. Playful and energetic, but easily lay down and snuggle. They look mean, but they are the most gentle dogs. My brother has a Lab/Great Dane mix. 90 lbs and would sever the jugular vein of any intruder. Very, very protective but a complete teddy bear around the people that are in the circle of trust. It's hilarious, when he has people over to eat, he growls when they take a bite. Smart enough to know they are eating the food supply that belongs to his pack.