During the hearing, Clara is asked if she has a surname. She says, "You can just call me Aunt Clara."
It was a common thread among almost all of the witches and warlocks who appear on the show to be called by first names only. Endora once told Darrin he wouldn't be able to pronounce her last name, and it was never mentioned again.
Samantha only used Stevens as a last name, with no reference to a maiden name.
A notable exception is Dr. Bombay, but it is uncertain whether 'Bombay' is his first or last name.
The title is based on the old proverb, "There's no fool like an old fool".
The dinner plates that Aunt clara clears off the table by witchcraft, is done by unseen wires attached to the plates, making them violently fly upwards.