If (for example) your enthusiasm before the game is at 6, then 1/3 of that is 2, so it will raise to 8. If the enth. is 9, it will raise 12. You get the pattern ;)
As long as it is above 5, it will be dropping. But it doesn't always drop an integer amount. For instance, from Tuesday to Wednesday it may drop from 7.4 to 7.1, and you'll see the same number, even though it is (slightly) lower.