For me, one of the major points of enjoyment in old movies is spotting the recurring character types in all kinds of films. Their familiarity is fun because I can anticipate how they'll fit in with the others, in the plot. And in many films such characters are played by very skillful performers whose obvious expertise is also enjoyable.
Not sure Marion Lorne's character belongs in the "Society Dame" category as much as she belongs in the archetypal Hitchcock "Mother" category along with Jessie Royce Landis in North by Northwest, Jessica Tandy in The Birds, and of course Mrs. Bates.
There is a second young woman with glasses type who is unattractive, intense and politically radical. Check out the the desk clerk woman at the nazi torture hotel in Foreign Correspondent and the nasty young woman who meets the plane to London in 2nd Man Who Knew Too Much. I'm sure she shows up in other films I have forgotten.