I suppose now and again maybe you can't put your finger on something, but if you spend some quiet time in thought about the games you play before dissecting them, most of the time you should be able to qualify why something did or didn't do it for you. And sometimes, perhaps, people might use it as a way of pissing a little on a game that might not be up their alley despite being competent and well put together.
Glad Sean got railed for that comment, though. Fallout 3 by absolutely no means played it safe, and while it can have the same mainstream appeal that any post-apocalyptic movie can have (i.e. everybody gets the concept and is intrigued by it), and is probably a bit more friendly to the average gamer than the original titles, I wouldn't say that it really went out of its way to go for mainstream appeal. Granted, even after 90 hours I still haven't seen the ending, which I guess could change things, but the rest of the game is certainly better and more original than that.