I played D&D as a Beast Master Ranger last year and role-played my wolf as a massive dog. The rest of the party got to pet her whenever we rested, and then she'd go and bite some monster's face off.
It was much more fun than just having her as a class feature. In fact, one of the best moments for my character in that game is when the wolf died in a dungeon, and he pulled her back out so we could find a cleric to Raise Dead.
