In "Decoy For A Dognapper," the perp, Buck Masters, tells the kids to mind their own business. Fred replies "Catching dognappers is our business. After all, Scooby Doo is a dog, and we love him very much."
"Jeepers, It's The Creeper": When Scooby returns the baby chick to its mother and kisses it goodbye.
"That's Snow Ghost": Shaggy, who has seemingly been turned into a ghost, falls into a pool of water. Instantly, Scooby yelps, "Raggy!" and runs over to pull him out. This dog won't even be in the same TOWN with a spook if he can help it. But if that spook is Shaggy? He ain't scary; he's my best friend.
Also for Scooby: in "Nowhere to Hyde", when the Ghost of Hyde kidnaps Shaggy, the dog starts looking for him. When he finds him, he runs over and snatches the table he is tied to without spooking once over the Ghost in the room.
From the same episode, the gang's concern when the ghost kidnaps Shaggy. Scooby wasn't the only one hunting for him and Hyde.