Continuity mistake: Kal-El's cradle arrives on earth, flies zooming past the Kents' car, which is driving in the opposite direction and crashes 500 meters behind the vehicle. The car keeps moving for about 200 meters and then pulls over. A brief shot shows an intact curb on the right. However, when Jonathan Kent gets out of the car, everything changes: The cradle has moved 700 meters and lays next to the car; and the immaculate field is now destroyed by a huge ditch.
Continuity mistake: When Otis is reading the paper about the meteorite found in Addis Ababa, the amount of chocolate in the candy bar increases or decreases depending on the shot.
Continuity mistake: When leaving the Daily Planet for the first time together Clark gets stuck in the revolving door behind Lois. He lets her go through ahead of him and gets in the next section as the door revolves. Cut to the exterior of the Planet when they emerge (just before they meet Rex Reed) and Clark is in the same section of the revolving door as Lois.
Continuity mistake: On the Golden Gate, the blue beetle skids and stops with the rear tyres on top of a painted white line. A frame later the car is on the middle on the white line.
Continuity mistake: The lights on the heliport keep swapping from facing the ground to pointing at the sky between shots.
Continuity mistake: The telephone poles close to the gap on the railroad disappear in the wide angles.
Continuity mistake: Inside the cab arriving at the Daily Planet, the fruit stall has no van behind. Immediately afterwards, a van appears.
Continuity mistake: In the extended version, when Superman talks with his father in the Fortress of Solitude about being a hero, one shot shows the crystals reaching up to Superman's waist. In the next shot they are at ankle level.
Continuity mistake: In the football field, all the player pass in front of Clark and leave him alone. In the next angle a player is passing by again.
Continuity mistake: At the police station, behind the fat cop there's a young cop picking up papers who walks to the left and stays there for a while. When the angle changes he reappears in the previous spot, repeating all the movements.
Continuity mistake: When Luthor switches the snow machine off, a wide angle shows the chamber totally covered in snow and ice, but the close-up of the vents and the walls surrounding are spotless.
Continuity mistake: During the Golden Gate Bridge crash sequence, a reversed shot of a life-sized 1972 Trans-Am braking hard is shown. The next shot shows a model car smashing into a model school bus, and the car is suddenly a 1965 Corvette. The fimakers have painted it red & white so it resembles the Trans Am. (Timecode is for Director's Cut) (02:09:10)
Continuity mistake: Liz places her kitty on her right shoulder and on the next shot the cat's gone.
Continuity mistake: When Ms. Teschmaker rests her arm on the file cabinet, a white roll of paper appears and disappears.
Continuity mistake: Right before Superman catches the burglar, he is standing in a steel intersection of the building. A second afterwards, he is in the middle of a window pane.
Continuity mistake: Before Superman lands on the sidewalk looking for Luthor, the aerial view shows no cars around. When he lands, the place is jammed.
Continuity mistake: When the Hollywood sign is falling on the girls, a close view shows a girl very close to a letter while her friends run away. A split second later, from a wide angle, the girl has disappeared.
Continuity mistake: Lois leaves the gas station but the reflection of the glass shows it still there.
Continuity mistake: When the three villains get trapped by the glass, Ursa's face and haircut are totally different.
Continuity mistake: At the heliport, a cork bulletin board on the wall appears and disappears between shots.
Answer: Superman has chosen to use his powers on Earth for the good of mankind. It would seem that lying to them would be an unneccessary thing to do, so it appears to be a personal choice. Interesting trivia: the closest he comes to lying is when he tells Lex Luthor to get Zod and company into the molecule chamber in the second film. Listen closely, he only says that it is a molecule chamber that takes away their powers, he never actually says that being inside will make them lose them, only that he wants Luthor to get them to go into it.
Jazetopher
That may be the closest "Superman" comes to lying, but Clark Kent does appear to lie. After the mugging scene in the first movie, Clark tells Lois the contents of her purse, and when asked how he knew (obviously from his X-ray vision), he says "wild guess" which was a lie.
jimba
Not only that but, he spent his whole life pretending to be ordinary so, in fact, he spent his whole life living a lie.