Around 1973 or so, Hanna Barbera was farming out it's animation work to Australia of all places, and the drop in quality showed. Even as a kid, I picked up on which later Scooby Doo episodes didn't look quite on model.

One reason I enjoy Sealab 2021 so much, is I suffered the original Sealab 2020 as a kid with all it's non violent preachy storylines. Surviving a week of school only to have characters on Sat morning stressing doing your homework also made me want to gag. ;)

With the exception of the live action Land of the Lost, this was about the only bright spot in an otherwise dismal kidvid landscape at the time.