The rules of the game.

They are always a somewhat annoying aspect of the game that I love. I don't mind if people play hard or even push the boundaries of legality by their play style... it's the somewhat vague officiating that really gets me annoyed. Some things just don't seem very clear to me and it just makes it difficult for me to figure out how to even play correctly. Luckily, I still enjoy playing hard, playing my best, but without that I might be inclined to avoid the basketball season altogether for lack of enjoyment.