I'm not just his fan, but I like his game (or used to like some of the elements of his game) for the following reasons:
Crazy passing shots, especially off the backhand (sadly it has been declining)
Maximum effort into shots
Let's leave antics and bad habits aside. We can talk about that later. We are talking about his game.
I think a lot of people who dislike Nadal/don't appreciate him here don't understand how difficult it is to generate spin with pace the way he does. I just appreciate that "maximum effort" element in his strokes that few other players possess. His straight arm normal finish forehand is one of the most beautifully violent yet biomechanically correct strokes I have seen. (Like most, I don't like his reverse forehand, either.)