I used to that when I was between ages 10 and 13. I had some board games at home. I would set the game up, and play it by myself. I loved having complete control of the game, without having to worry about cooperating with another player (who often blatantly cheated anyway). My parents never understood that, and kept reminding me: "you need to play this kind of game with a partner, not alone!" At the same time, they rarely played those board games with me. Oh well.