For me, it's "Lawman Barney," following closely by "Mr. McBeevee." The first is masterfully written, and the second is touching and inspiring.

Without a doubt, the episode where Opie accidentally kills the bird. Also, liked the one where an old beau of Aunt Bee comes to visit, hoping Andy will buy him off to leave town.

The Barney in the choir episode, the later fun girls episode where Helen and Thelma Lou are jealous after catching the boys with the fun girls at the courthouse, the Lydia Crosswaithe/Goober episode, the Ernest T. Bass How Do You Do Mrs. Wiley? episode. You're right, narrowing it to one is impossible.

Looking at the list of episodes I could easily name twenty great episodes from the first five years and twenty very good episodes from the color years. Some of the sentimental ones were my favorites before, but now I sometimes enjoy the harder comedy episodes a little more.
B&W:
Aunt Bee the Crusader (if I had to choose only one)
Goober and the Art of Love
Man in the Middle
Color:
Goober Goes to an Auto Show
The Lodge
Floyd's Barbershop

Most of the color Barney episodes are great and I always keep an eye out for Helen, the Authoress. It's not a great episode but I sure like seeing Elaine Joyce as Mavis Neff, and Floyd and Howard's funny conversation about her ("Yes, I hear she's rather forward").

There's probably over 50 I say are my favorites . To narrow it down to one would be impossible. I've seen some over a hundred times each in my lifetime. They never get old.

Even the much disliked Warren episodes are classics to me.

I agree, Vito. It's probably the only series I've seen where even the weaker episodes still have funny scenes that make them well worth watching. The only exception I've seen is the last episode, which I've seen a few times, and I consider that really the worst episode of Mayberry RFD. I think Andy and Helen getting married was meant to be the last episode.

The Dick Van Dyke Show might have good scenes in every episode too, but that show is carried by the incredible chemistry between DVD and MTM. But, to me, TAGS is overall the best series ever. Even some episodes of Seinfeld don't hold up as well, because TAGS hits on a somehow more comforting emotional level. Over time, small laughs coming from true emotions can often hold up better than big laughs built on funny jokes. Although, all three of these sitcoms are truly great shows.

I'm not too big a fan of season 1 and some of 2 where andy is the funny guy with Ellie. I like the episodes starting a bit into 2 and especially when Thelma Lou arrives until the end. I like Helen and Thelma lou.The RFD thing nah. The houseguest and aunt Bea with the crying baby were stinkers in that good timeframe. I can still watch season 1 because I'm that big a fan in general of the show.
I always say tdvds it's the most consistent sitcom with maybe tmtms ever.

Big Seinfeld fan when it ran no idea why I don't watch it now.
Funny scenes are great to bash around with friends. I'm like that with the stooges and the great Jerry Stiller king of queens scenes.

I just love the Andy/Barney relationship and you knew that Griffith was really laughing at Don. It's one of the few shows I really laugh out loud even though I've seen them tons of times. I have to say I can honestly say Malcolm Merriweather is top of the list. The way Andy uses his Cockney slang is hilarious. I hate episodes when Helen gets jealous because she becomes almost sinister.

I love any episode that makes me tear up (Bed Jacket) or makes me bust a gut when Barney talks about the maximum security cells. Also love The Darlings "Aw Pa cant I look at the pretty man?"

How are the cells maximum security? The keys are kept in the drawer.

Thinking now the color episodes when Barney's returns or Andy visits I really have a softspot for.

All the Warren episodes to me are absolute classics too. Ha...ha...ha?

The first one that came to mind for me was "The Pickle Story." Really tough to say which one is my absolute favorite.
I will say though I'm an Elinor Donahue fan so the Ellie Walker eps are indispensable for me.

Thinking now the color episodes when Barney's returns or Andy visits I really have a softspot for.

All the Warren episodes to me are absolute classics too. Ha...ha...ha?

Another way to say it--a little Warren goes a long way. Warren sleepwalking and hitting on Helen was pretty funny.

Another way to say it--a little Warren goes a long way. Warren sleepwalking and hitting on Helen was pretty funny.
I'm the only person on Earth that likes Warren on tags and Joe besser on the 3 stooges. "Not so hard"

I think the big problem with Warren is when they tried to pair him up with the sillier characters the way Barney had been paired up with them. The problem is that Jack Burns didn't have the chemistry that Don had with them, which really made episodes like The Cannon, A Warning from Warren and Lost and Found a chore to sit through. Episodes where Warren doesn't have to deal with silly characters (The Organ, The Legend of Barney Fife) he's a lot more tolerable.

For my favorite episodes I'd have to say The Haunted House, A Black Day for Mayberry, Three wishes for Opie (Even with the angry Helen bit at the front) and Mountain Wedding (Though any black and white episode with Ernest T Bass is a hoot)

Yup I'd say you are the only person on Earth who likes the Warren episodes (Ha ha ha) and Joe "Not so hard" Besser.

Vito, I misunderstood your post #10. When you put the ha, ha, ha at the end I thought it was tongue-in-cheek, meaning you didn't like Warren.

Vito, I misunderstood your post #10. When you put the ha, ha, ha at the end I thought it was tongue-in-cheek, meaning you didn't like Warren.
That was Warren's signature bit not letting people respond. Ha ha ha. It just cracks me up.