I think many games have important events that aren't obvious to inexperienced players/spectators. In football/soccer, for example, off-the-ball movement is very important, but usually ignored by inexperienced players.
How about tactical choices like which players to put in which positions, who to guard whom or which zone, etc.? These choices are often made before the game and may only have effects towards the end, when the speed difference between two players becomes larger due to tired legs.
