[Shaggy and Scooby realize what's happening and take off running.]
After running from the skull, Shaggy wishes he had a ham sandwich. A ham sandwich appears right out of nowhere. He then complains that it needs mustard. And then a jar of mustard appears.
Shaggy: This has gotta be my imagination, otherwise, I'd be scared stiff!
Shaggy then asks for his imagination to cut the sandwich in half. The nearby suit of armor drops its ax right onto the sandwich, cutting it perfectly in half. Scooby and Shaggy run away...after which Shaggy returns to pick up the sandwich.
In the episode "Mystery Mask Mix-Up", Shaggy tries pretending to not be scared to keep the masked figure, Zen Tuo, away. How does he do this? He picks up a stick and draws a line on the dirt floor, daring Zen Tuo to cross it. Shaggy does this several times before Zen Tuo finally just takes Shaggy's stick and breaks it.
Also from the same episode, as Shaggy and Scooby escape Zen Tuo, this exchange occurs as they board up a door to hide behind:
Shaggy: Ha! He won't be getting through that door!
[The entire wall the villain's behind lifts up like a curtain.]
Shaggy: ...And wouldn't you know he comes through the wall?
Zen Tuo wasn't done being funny, either:
Shaggy: Don't you know it's illegal to shoot off fireworks and wreck a store room?
Zen Tuo: We will build a new store room!
Shaggy: I wonder who's gonna build a new us?
In "A Night of Fright Is No Delight", Shaggy takes the fish's fish food for his sandwich, and the snarling sound the fish makes is just hilarious.
When the walls start closing in on them when Scooby attempts to "feed" the organ, they ask for Scooby to do something. He agrees, and hides in the storage area of the bench.
Shaggy and Scooby-Doo's barber shop skit in "Who's Afraid of the Big Bad Werewolf?"
Shaggy:[grabs werewolf's paw] Step right in, sir. No waiting. [places him in barbershop chair] I know, just a light trim, sir. We're all wearing it a bit longer these days!
Scooby: Bad nails!
Shaggy:[having given the werewolf a short, uneven haircut] You have a dandruff problem, too, sir! [the werewolf begins growling] Something wrong, sir? Scooby, scat!
This bit of dialogue:
Shaggy: Oh, why don't I just keep my mouth shut?
From "Never Ape an Ape Man", as Shaggy and Scooby-Doo try on costumes:
Shaggy: Give me liberty, or give me pizza pie.
From the episode "What the Hex Going On?":
Shaggy: Like, I've found a clue.
Fred: Groovy. What is it?
Shaggy: Him. [cut to Shaggy pointing to the ghost of Elias Kingston with his hand on Shaggy's shoulder]
Scooby and Shaggy hiding from Mr. Hyde in a TV set in "Nowhere to Hyde".
Hyde turns on the TV. Shaggy pops up, dressed as a clown.
Shaggy: Hi, folks. Uncle Happy Time here, once again, with your favorite dog star, King of the Wild Blue Yonder.
Scooby:[dressed as a pilot, waving] Hi, kiddies!
Hyde changes the channel. Shaggy and Scooby, dressed as an American Civil War soldier and a Native American, pop up.
Shaggy: If you don't sign the treaty, Running Dog, we'll take back the trinkets and beads!
Scooby: Uh-uh. Indian giver!
Shaggy:[sticking his finger into Hyde's stomach] Then go!
Hyde lifts up the TV.
Shaggy:[chuckles] You know, you ought to get this set fixed!
The Open Sesame moment in "Go Away, Ghost Ship": A hidden warehouse is guarded by a (mechanical) talking skull that demands a password. Fred tries "Sixteen men on a pirate's chest," which doesn't work; Velma tries "Yo ho ho and blow the man down," which doesn't work either. Shaggy tries "Yum yum yum and a liverwurst à la mode" as a joke and it does.
Shaggy: Wow, some password!
Redbeard turns out to be Genre Savvy enough to realize that Shaggy and Scooby sabotaged a stew they made for him, so he makes them eat it. Fortunately they put soap in it so they spit bubbles at him to escape.
In "A Gaggle of Galloping Ghosts", the vampire tells the gang that they're not welcome in the castle and tells them to leave. Velma tells him to stop that.
During their trip to the fortuneteller, she warns them that they're in danger of "evil forces from the world of the dead" in the mountains. Scooby hides under the table, being afraid of the werewolves.
Shaggy:[angrily] There are no werewolves, Scooby! You get back here!
In "Which Witch Is Which?", after only finding a voodoo doll of Zeb: