Dave Foley wore a wig during the first episodes of Season 4 because he had "worn" short hair as the character Astronaut Al Bean in the 1998 TV mini-series From the Earth to the Moon (1998). Steven Root also acted in this miniseries as Chris Craft, director of NASA Mission Control during the Apollo space flights.
This season features new opening credits with specifically created scenes of the cast.The opening credits for the first three seasons featured random shots of New York City, showing plenty of cabs and streets scenes..
Gone are all the knick-knacks, stickers, and other decorations that had usually hung on the wall in front of Beth's desk.
The address Dave gives the 911 operator of the Criterion Building is actually Mount Sinai Hospital.