What I love about this series is that you often get more pieces than you need. This leaves you with more possibilities, and you get a lot of forehead-against-wall moments, when you finally figure it out :)
Perhaps you become a superstar a little too quickly. The game is awesome, but it could be even more challenging, if you experienced some setbacks during a career. Maybe an injury that caused you to lose some skills?
Not all people like solitaire and difference games. I happen to like both! If only the solitaire games were different as well as the difference games are different in their differences, it would really make a difference (are anyone following...??)!