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I'm sure Stewie has told many people that they suck, but one time stands out in Family Guy history. In episode To Live and Die in Dixie the Griffin family has been placed in the witness protection program and sent down to the deep South. Upon opening a closet in their new house Jeff Foxworthy is inside and delivers a horrible joke: "You know you're a redneck when your gun rack has a gun rack." Stewie immediately dishes out a "YOU SUCK" and slams the door.
Memorable Family Guy episode quote: "Guess who? Sorry to leave you so many messages. Just lonely here. Thinking' about the muscly-armed paperboy. Wishin' he'd come by and bring me some good news." - Scary Old Man on Griffin answering machine.