When the group is leaving the office of Sterling Cooper after their weekend meeting, Joan walks by the front desk of the office through three camera angles. In the first angle, she wearing a scarf on her head which hangs loose over the back of her neck, then from the next angle, the scarf is tucked in under the collar of her jacket, and then from the last angle, the scarf is once again untucked.
In the closing scene, when Don crosses the street to his new apartment, the taxi that drives by is a 1974 or later model Checker. The silver painted girder type bumpers were first installed on Checkers in 1974.