The Fonz becoming a major player.
History is truth and the show was already a hit before Henry Winkler's character controlled the show.

When they all wear the leather jacket to run Officer Kirk out off town. Howard, Marion and Shortcake should off stey home, hana

I am sorry buna, Arnold was not the interest mans hana

𝙽𝚈𝙲 []

I found the first two seasons boring. The show got better, during the 3rd season, when the Cunningham house changed, switched to a live studio audience, and the theme song changed (
Rock Around The Clock
was boring to me).
Though, I gotta admit, that show should have ended after Season 7 instead of dragging on to Season 11.

The first three seasons were great but the success of certain catch phrases and other things led to their overuse.
I didn't mind it one or two times but Richie singing 'I found my thrill…' any time they needed a cheap laugh. The crowd went right along with it, screaming and howling.
Ralph Malph saying 'I still got it'.
Joanie saying 'Hunk!'.
Fonzie adding 'amundo' to words. Always being able to control machines, lights, etc with a well positioned fist bump or being able to instantly have girls come running ready to kiss with the simple snap of his fingers. In some situations these were fine. Not all the time, though.
Chachi's 'wah wah wah'.
Al's 'yep yep yep yep yep'. I found Arnold to be much funnier.
Potsie singing. This is another cheap way to fill time on the show.
The actual jumping of the shark didn't bother me but I do recognize that episode was a turning point for the series. It looks much better compared to what was yet to come. Like the awful ranch three parter.
Mork from Ork. Wow, were those awful.

Lavert and Shirli were a couple of dogs, buna

Mostly all Fozzie dancing. Dance with Missus C, dance like a Russian, dance and sing like Elvis Vegas look 20 year before Elvis was sing Vegas and also dance with Ruchi Cunningham, hana

Fozzie wearing glasses, hana

Turning Fonzie into a clown and having him do things a greaser would never do (many examples have been listed by other posters in this thread).

Fonzie dancing like a Greek to sign off Lucy from Dallas, hana

Mork from Ork.
Trump lies:
Mexico is going to pay for the wall.
I can stop federal funds.

Fonzie having a toothache and being afraid of the dentist.

Excellent rundown kaydie I was going to say "I found my thrillll" for sure. Who the bleep would sing that in front of their parents???
You'll kill everyone!
But Ice Cream Cake!

Honestly there are too many to list, but here's a few:

• The gang singing and dancing to 'Pumps your blood' after Potsie failed his biology test
• that 3 part episode where they all go to a ranch, especially the scenes where Fonz and Richie spontaneously start doing choreographed line (?) dancing and an obvious stunt double pretends to be Joanie in a runaway wagon
• shark jump in a leather jacket
• The flamboyant 'tough, street' gangs who showed up regularly, particularly the gang who tried to force Joanie to make out with all of them until Fonzie and the Big Ragoo showed up and defeated them via ballet dance
• 'I found my thrrillll' - STFU
• Fonzie throwing a depressed dog a party (complete with dog-food cake) in Arnold's -yah real coooool