Expectations affect pretty much everything to some degree. When something doesn't meet expectations it is immediately obvious and causes a reaction, its then up to the person to realise whether their reaction was appropriate or if they were thrown off by expectations. Expectations don't change the actual quality of a game, but they can affect the way people judge the quality of a game. How much you enjoy a game is all down to your subjective preferences, it's why your opinion on a game can shift, the game didn't change, but what you enjoyed about it did. Expectations can play a part in that and some people can look past them and others can't.
One non-gaming related example happened to me recently. I bought a drink, it was flavoured water and I had a pretty good expectation of what it was going to be, but when I tried it, it was revolting. I put it down in disbelief at what I just tasted. But then I looked at the label and description in detail and realised that it just wasn't what I was expecting and after trying it again, I could see that my initial strong disgust was out of line, I still didn't really like it, but I'd been so thrown off by expecting something else.







