1. Many game developers are introverts - In Psychochild's words, "a week of hanging around other people and trying to maintain our social manners is actually draining for us, not invigorating."
2. It's expensive. - Pass? US$ 1850.00 Airfare? US$ 250.00 Hotel stay for six nights? US$ 750.00 Meals for 6 days? US$ 150.00. Some cheap ways to be at the GDC, Psychochild says, include living in the area and getting a free pass by writing a few articles for a media site. Or, might we add: just read up the QJ.net GDC updates.
3. Not all of the talks are good. - Some may put effort on their talks, and some may only put together their slides the night before. To think that you're forking over a thousand bucks for it...
4. The audience could be bad. - The intelligence levels of the members of the audience tend to vary because "you realize that the intended audience for the conference isn't the game developers, it's actually the wannabes that want to break into the industry".

spend a grand or two after hotels and passes, see same old windbags talk about the same stale ideas, silently chuckle to self that everyone seems to claim expertise in what is probably their weakest area, make weak effort to pass out business cards and ignore the fact that conglomerates are sucking the life out of the business as surely as they did to the music business in the past ten years, silently cry at seeing the 15th copycat game of what was an original idea ten years ago, drink, sleep, repeat, go home

Via Psychochild's Blog