Mulder and Scully always call each other by their surnames. Mulder tells her not to call him FOX, because he hates it, and he rarely calls her Dana. See more

Goofs

Throughout the series when we see a closeup of CGB Spender's/The Smoker's ashtray while he is extinguishing his cigarette, the filters of the "smoked" cigarettes already in the ashtrays are perfectly white, while they should be yellow/brown from the nicotine-smoke. This indicates that they are props, placed there before shooting and not cigarettes smoked by the characters. See more