I think it is more the idea of variety. I know for me, even the best games get stale and I like a change of pace. Take SS Billiards for instance. He has Medieval Madness, Attack From Mars, Big Bang Bar and Twilight Zone...but I have played them all a million times. He gets a "new" game in like an older title like Police Force and it gets played a ton because people like variety and to see something new.