Joan cuts her finger deeply during New Years Eve with Greg, requiring stitches. Yet 2-3 days later at the partners meeting, she has no bandage nor any sign of injury.
The pattern of fresh paint on Anna's wall changes between consecutive shots.
When Don first arrives at his office he hands his coat and hat to his secretary, but both are already hung up when he steps inside.
The imported Japanese monster film, Gamera, had not been released until after the date that the episode was set.
Abortion was illegal in 1963, and any woman having one was a social pariah, yet, both Joan and the doctor discuss it as though it were a common everyday procedure, when in reality, a doctor of that era would be horrified to hear a patient had one, let alone two. Also, a woman would be embarrassed to admit that she ever had such a procedure.