Why should you evaluate a game? Why not just jump in with both feet and play? Well there are more issues here than what guy will take the last piece of pizza and who takes too many potty breaks.
Pavlov made some rather powerful points about positive conditioning using only a bell, some table scraps, and a dog with overactive salivary glands. In short, whenever the bell rang the dog began to drool because the K-9 was always fed when he heard the ringing. The tolling of the bell meant food was on the way. Poker players are conditioned in a similar way, but instead of table scraps, our positive reinforcement comes in the form of little green pieces of paper.
If you ask someone why they made a particular play, they often reply, "I wanted to see what would happen." Let us be clear about this. If you're not making a play to either win money or prevent yourself from losing money, you're making a pointless play.