Since I very rarely play games for their challenge, I definitely don't really consider myself great by any stretch of the imagination; heck, I'm probably a bit reluctant to even call myself "good", "decent", and possibly even "competent". Most games I turn down the difficulty to easy because I wish to avoid the frustrations of playing on harder difficulties and just want to enjoy the story. In the rare cases where I do get into multiplayer games, I usually do horribly and have a bad tendency to leave myself open to a wide variety of basic tactics.
However, this is not really a complete lack of skill on my part; it's just a lack of interest. I play games either to just enjoy their story or because they're just plain fun to play, not to overcome the challenges nor to "defeat" the game. In fact, I usually don't give a damn about winning at anything or completing something just to say I've done it. If I'm not having fun playing a game, I just stop playing it regardless of how far along I am.
Actually, I've managed to surprise myself on several occassions and end up being better at a game than I thought. Nothing spectacular of course, but sometimes my preferrence for experimentation and atypical playstyles yields some unexpectedly good results. When the normal approach doesn't work, that's usually when I can get the chance to demonstrate what I'm really capable of; it's problem-solving really.
But most of the time, I just don't care enough to bother even trying to be "good" at games. I either play them for fun or for their story, not because I enjoy overcoming a challenge.