For regular seasonal games, there are three options:
Take it Easy - increase enthusiasm, but you team tries less
Normal - doesn't really affect enthusiasm
Crunch Time - Decrease enthusiasm, but your team tries harder
For playoffs, however, things change.
If one plays "Playoff Normal", their team tries with normal effort and they will receive the same enthusiasm boost as if they had played TIE in a season game.
If one plays Playoff Crunch Time, the team will try harder to win and their enthusiasm will stay about the same as it was before the game (the same effect that a regular "normal" effort has in a seasonal game).
I didn't explain this clearly but there are a few threads in the help forum that explain this.