Additionally, it forces me to stop playing 'hope chess'- I can't put my faith on tactics because the computer has already accounted for them in its defense. This is where the computer stops blundering pieces and doing unfavorable exchanges. For me, that would mean the 1200-1400 elo range.
I just got a copy of Chessmaster Grandmaster edition (very hard to come by) to try to progress against some of the tougher (for me anyways) computer personalities.
