Expectations of game design
Experience in games is paradoxical because of expectations. It makes you a worse game designer.
When you play a game, your expectations will be larger on the next game.
These expectations put you to discard many otherwise developable ideas. They also make it harder to enjoy subsequent games even if they did diverge from earlier ones a lot.
Expectation, or anticipation of what's to come can be still enjoyable in itself. Getting something else than you expected for can be enjoyable, or then not if you do not appreciate it.
Expectations steer what you create. To the point that what you create is so safe that it isn't exceptional.
You can't completely drop the expectations because you experience all the time. But you can be aware the remaining are there.
Also some expectations are all right. Deliver the damn pizza if you make someone expect one! But don't give me a dubstep if I'm expecting for the fricking Turrican "the wall".
And before you can deliver you should know what's been there and how it's been done. That's why I still go to study (bad and good) C64-era games or otherwise pick up titles over the way.
The downside is that it raises your expectations to the point that you can't create anything because you can't surpass your own expectations.