Most of us have had it happen. We get hyped up about a game that looks like it's the most awesome thing ever, or it has some cool innovation that no games ever done before. Then you play it and your very disappointed for any number of reasons. give us some examples.

Sonic Next-Gen (or any other 3-D Sonic Game since Shadow The Hedgehog)
Spider-Man 3
Shawn White Snowboarding