Tam's recent post about solved games really crystallized something for me with regards to why I do and don't like certain games. In particular why I will sometimes really like the concept of a game and yet end up absolutely loathing it in practice. In a word, metagame.
I've come to realize that the existence of a codified metagame for something is a pretty good sign that I won't want anything to do with it. If there's a way of doing things that is the way, the truth, and the light, then I get to choose between following the crowd or trying to go my own way knowing that I'm actively not playing optimally. The former tends to lead to me getting bored quickly, particularly since the one right way rarely ever syncs up with the way I want to play, and often relies on degenerate strategies. The latter puts me in a spot where I don't get to take joy in improving, since I'm aware that I'm actively not playing 'the best way'.
Beyond that, I'm being forced to spend time figuring out how to play the game 'properly' rather than actually playing the game. Part of the problem with metagame for me is that it is, by definition, external to the game. So I end up having to look for FAQs, wikis, or even *shudder* official forums to even begin to figure out what I'm 'supposed' to be doing. And then, without fail, I learn that I chose the wrong class, hero, skill set, or whatever and I can either start over completely or bull on with the knowledge that I'm 'doing it wrong'. At least if it's a single-player game I can take comfort in playing the character I want to play even if it isn't optimal. In a multi-player game there's the added joy of other players more than happy to tell you that you're stupid and wrong if you dare to step outside of the accepted orthodoxy.
My roots in tabletop role-playing, where metagaming has long been viewed negatively, may also enter into this. For me playing a game is about working within the bounds of the assumptions that are made by the system. Avoiding use of out-of-game knowledge as much as possible is part of this. If a game is well designed and things are messaged properly, I should be able to figure out everything I need to know to play well without having to resort to outside information.
Ultimately, the more time I'm having to spend playing the metagame instead of the actual game, the less I tend to enjoy myself. I want to do my learning as a part of playing, rather than as a prerequisite to even getting started.