Guest,
I'm sorry you feel this way, but calling the people here "incredibly stupid" isn't likely to endear you to anyone.
Yes, there are 'in-jokes', yes some people are rude, but as Bagpuss says, the vast majority of people here are very friendly and helpful.
Think of it as joining any existing group of friends - take time to get to know people, and don't expect people to understand you straight away.
Follow this advice for a bit, and you'll make some great friends. If you choose to walk straight out - we won't miss you: because we don't know you...
Ed