Here's something I wrote that I feel gives an intuitive explanation:
http://www.jellyjuke.com/a-conceptual-explanation-of-the-hot...
http://www.jellyjuke.com/a-conceptual-explanation-of-the-hot...
- A player could be sick
- A player could have an minor injury they are playing through
- A player could have not eaten properly before the game
- A player could have been practicing a new shooting form and not quite adjusted properly yet
If you can have bad days, by definition all the other days are good days even if they are only "normal" days.