Quagmire mentions that he has a girl tied up in his basement, yet in "420" he mentions that he found James under his house, indicating that he has no basement.
When Stewie is talking to Brian about Chris Farley, they are talking about the film Tommy Boy. However, Stewie mentions tapping on the glass causing him to fall down the hill which happens in the film Black Sheep which also stars David Spade and Chris Farley.
Quagmire criticizes Brian for not being involved in Dylan's life. However Quagmire has at least four children that he knows of, all of whom he willingly abandoned. Also, although Quagmire says that Brian never takes action despite his liberal beliefs, Brian did start a campaign to legalize pot in "420", and held Mayor West hostage to legalize gay marriage in "You May Now Kiss the...Uh...Guy Who Receives". Also, Quagmire states that Brian always hits on Lois. However, Quagmire hits on Lois as well. This makes Quagmire seem very hypocritical.
Quagmire seemingly only discovered the internet in "Family Goy" and primarily was only interested in porn, yet knows you can find out all about the economy.