Carolyn Jones is exquisite and John Astin is hilarious

These two people (as well as the cast in general) had GREAT chemistry.
Neither seemed to do much beyond Addams Family, but they are wonderful here.
Jones looks absolutely beautiful and Astin has manic energy and even uses physical comedy as part of the program.
I think they were given great material to work with, and it really brought out the best.

For some reason I want to contrast it with the beloved I Dream Of Jeannie.
While Jeannie was very agreeable and a fun watch, I always felt they were actors saying their lines. Not much inherent appeal, except for Barbara Eden in her skimpy outfits, and the interactions were clever in their befuddled fashion.
Jeannie was well-written enough but the acting seems a little "pro forma", while the Addams Family almost feels - in an incredibly weird way - like an actual Family.

YMMV