What is it and why?

There are so many favorite lines,but one good one is when Mr.Drysdale said he'd draw up a check for $11,000,000.00 and Granny said she wanted cash.Jed said,"We do favor cash."

I also liked when Jed described Elly May as having,"More curves than a goat's path."

Jethro had his memorable lines,like when he was trying to recite a poem;"How do I love thee?Let me cypher the ways."

The exchange between Miss Hathaway and Jed contains one of my favorite quotes.
Jed is telling Miss Jane about Jethro having attended Oxford School. Jane says, "I take it he went to Eton as a boy?" to which Jed responds, "If I know Jethro, he went to eatin' the minute he was born."
Erica

I like all of the quotes especially when Granny says what she is cooking for dinner she makes crazy thing for them to eat.

Two of my faves:

As Jethro and Jed are entering Marineland (they think Jethro can join the Marines there)they pass under the entrance sign saying "Feedings at 9:00, 10:00, 11:00, 1:00, etc., etc.," Jed says... "Boy, I think you're goin' to like the Marines!"

After Jane Hathaway gives Jethro a book as a gift for his elementary prep school graduation and begins speaking words of encouragement to Jethro in Latin, Jethro is oblivious (fascinated by the ticking of his new Mickey Mouse watch)and Jed says... "Miss Jane, I believe you're castin' your bucket down a dry well."

Wonderful writing!

Jed tells Elly May: "You're showing more meat than a butcher's window!"

Jed - seeing a sad-looking Duke (the dog) - lying on the ground:

"Duke looks lower than a snake's belly in a wagon rut".

And Granny with her "grits 'n' jowls 'n' possum innards".

I also like Jed's words for being tired: "plum tuckered out"

"You're more fetchin' than a fat hog on market day"

Jed-Wellll doggies, and Someday I'm going to have a loong talk with that boy.
Jethrow-Hot Dog!

Jed answering the phone, when he works at the bank:

"Commerce bank - you need money ? Well come right on down and get it !"

as I said before, there's so many! Ecspesially in the early episodes, like this exchange between Jed, Jethro and the headmisstres of a prestriguos private school where they want to enroll Jethro in:

Mrs. Potts (the headmistress)-"You do know we charge tuiition".
Jed-"Yes ma'm, ah figgered thet".
Mrs. Potts-"And it is quite beyond your means, I am sure".
Jed-"Well ma'm, if thet means it costs a lot; anythin's fine as long as it's not over twenty-fave million".
Mrs. Potts-"TWENTY-FIVE...MILLION"?
Jed-"Yes ma'm"
Jethro-"Yes ma'm".
Mrs. Potts-"You have twenty-five million dollars"?
Jed-"Well, not on me, no ma'm-ya see, my neighbor Mr. Drysdale, he's holdin' it fer me down t' his bank. And he ain't chargin' me nuthin fer it".