Here is perhaps the greatest Barney Fife dialogue exchange, from the episode "One-Punch Opie," where Barney lectures Andy on the necessity of stopping children from becoming delinquents. Of course the dialogue loses a lot without Knotts's superb delivery and his nervous pacing and gestures. He was unique.
BARNEY: I don't like it. I don't like it one bit.
I tell you this is just the beginning: goin' around breaking street lamps -- city property, mind you! Next thing you know they'll be on motorcycles and wearin' them leather jackets and zoomin' around. They'll take over the whole town... a reign of terror!
ANDY: Barney, these are just boys you're talkin' about. They're only about 8 years old.
BARNEY: Yeah, well today's 8-year olds are tomorrow's teenagers. I say this calls for action and now. Nip it in the bud. First sign of youngsters goin' wrong, you got to nip it in the bud!
ANDY: I'm gonna have a talk with 'em. Now what more do you want me to do?
BARNEY: Well, just don't mollycoddle 'em.
ANDY: I won't.
BARNEY: Nip it! You go read any book you want on the subject of child discipline and you'll find that every one of them is in favor of bud-nippin'.
ANDY: I'll take care of it.
BARNEY: Only one way to take care of it.
ANDY: Nip it.
BARNEY: In the bud.