"Sick as a dog...
but havin' the time of my life!"
"Alright alright alright you smell gas, course you smell gas what do you think this car runs on coal"
This is not a line, per se, but one of the funniest bits in all of TAGS, in my opinion, is when the steering "thing" starts coming toward Barney like a snake. Meanwhile, the background music is playing the snake-charmer music. Perfection! It could not possibly get any better than that!
I think it's my all time favorite scene. Thelma Lou gets to show her comic timing skills, chattering away about how much she loves a pretty farm and then, without skipping a beat, seeing the steering wheel coming up and breaking into a full scream. The best.
Rule #1: OBEY ALL RULES!