The portrait of Barnabas was usually in the foyer at Collinwood, and the camera would pan mysteriously to it when something ominous was about to happen (accompanied by eerie music)
The role of Dr. Julia Hoffman, played by Grayson Hall, was only supposed to last a few weeks, but Hall's husband, Sam Hall, was a head writer for the show and eventually made a star out of the character.
David Selby was written out because he developed appendicitis and had to undergo surgery. He recovered as the show was canceled and was able to star in the final theatrical spin-off, Night of Dark Shadows (1971).
Angelique: You wish you'd never met me. But you did. And nothing can change it... Come to me. I command you to turn around. Look into my eyes. Deep into my eyes. You have no will of your own. You cannot resist me...