Important correction. 'Cause as Willie says, "if it ain't Scottish, it's crrrraap!"
Every episode has at least one line that is funnier, wittier, and/or more profound than any line in any other television show. Sometimes an episode will run off so many great lines you get mad because you know you'll never remember them all.
My favorite from this past Sunday? Homer discovers a 60's era ambulance on the used car lot:
"I bet a lot of hippies were denied care in this thing! Heh heh, injured hippies."