It is! I have this Lost based game I'd like to start, but 'm like mmk, have no idea what's going on, I could be wrong, etc etc. And it makes playing certain characters a pain, because you have no idea what's going to happen to them or where their allegiances lie or what their backstory/futurestory is like. In other canons you can make your own shit up, and if it doesn't match up with canon you can still deal. In "Lost"? You can say your pup is like the evilest thing ever to come out of Eviltown, or the most mundane thing ever to come from Yawnstown, and you can be so wrong it ain't even funny. And you CAN'T deal because sometimes those details revealed in canon are very important to the overall mythology of the show.