Starring: Robert Patrick, David Duchovny, Annabeth Gish, Gillian Anderson, Mitch Pileggi
Deep Throat - S1-E2
Revealing mistake: Mulder pulls away from the hotel after telling Scully he is going to shower and then they'll leave. The tire marks from previous takes are visible on the pavement.
Deep Throat - S1-E2
Revealing mistake: During the hard braking due to avoiding the collision with the unknown agency cars, notice that there are stunt people sitting in the car instead of Mulder and Scully. (00:21:15)
Clyde Bruckman's Final Repose - S3-E4
Continuity mistake: Clyde Bruckman commits suicide by placing a plastic bag over his head until he asphyxiates. However, when Mulder and Scully first discover him you can see in the shot just before Scully holds his hands that there is no plastic bag around his head (may only be visible in widescreen format). (00:42:55)
The Post-Modern Prometheus - S5-E5
[After spilling coffee on his lap.]
Mulder: Great, now my crotch will be up all night.
Trivia: Scully's father, Scully's older brother, and the man Mulder thought was his biological father were both named William. (The father who raised Mulder went by "Bill, " as did Scully's brother.) Mulder's actual biological father, Cancer Man, was played by William B Davis (who also goes by "Bill"). Scully and Mulder's son was also named William (before being adopted and having his name changed to Jackson).
Question: In a vast majority of the episodes, whenever Mulder and Scully investigate some mysterious or paranormal phenomenon, Mulder believes that some unknown force is responsible but Scully always has a rational explanation for what is happening. In other episodes, when Scully herself is caught up in something mysterious, she is the believer but Mulder is the skeptic. In those episodes, why would Mulder be skeptical about an unexplained phenomenon considering that he a was witness to his own sisters abduction and he saw many strange things that defied explanation while working for the F.B.I.?
Answer: A variety of reasons. Just because Scully saw something unusual does not mean that it was. Mulder always needs concrete proof before he'll believe there's some otherworldly explanation for unexplained phenomena. He's too experienced to take a novice's explanation as fact. It is also a plot by device by the writers to switch the tables on the characters to make it more interesting and to let viewers see another side of their relationship.
Answer: As he stated many times throughout the series, Mulder needed Scully to be sober and skeptical. Whenever Scully's skepticism wavered and she started questioning her own rationality, Mulder would try to restore her sense of skepticism, because he needed her to be clear-thinking.
Charles Austin Miller