Revealing mistake: When Brian tells Brooke "I understand", after he thought he was being rejected, his left ear disappears for a single frame.

Revealing mistake: Watch closely when Brian is demonstrating orbit. The apple can be seen to go through Peter's hand a couple of times. (00:07:50)
Revealing mistake: When Peter leans down to get the basketball, a dot briefly appears on his shorts, then disappears almost immediately.






Suggested correction: Quagmire considers the rest of them to be his best friends. He isn't drinking because they can't drink. He is complaining because since his friends can't drink - he won't drink, so he is still pissed.
It's still a plot hole considering Quagmire's age. I think the writers messed up big time.
You make a good point, but it's awkward to be that one person who is drinking while surrounded by people who can't. So, I understand the correction that was submitted above. Because his friends are not drinking, he now feels that he can't.
It's 100% a mistake. Quagmire simply would buy them alcohol the same way Brian did when they realized he could.
ctown28 ★