Winning is everything. In my younger days a friend and I would go to the arcade run up credits on a machine and sell them. Every day we could make enough for a pack of cigarettes and a six pack of beer.
Today, I play BOPP at home to build credits. I play a one player game, a two player game, three player game, and a four player game, for a total of ten games, then see how I have increased the number of credits. Doing that gives me a nice long game time with some sort of end goal.