Continuity mistake: After Superman prevents the Statue of Liberty from crashing against the street, when he passes Central Park, there's a wide angle of the Statue flying and Superman is nowhere to be seen.
Continuity mistake: When Superman arrives at Lois's balcony, a plant on the left is away from the door. When Superman leaves and Lois asks him to take her with him, the plant is next to the door.
Continuity mistake: When Lacy is seducing Clark in the office, the things on the table change positions between shots. Watch how the glasses move around, for example.
Continuity mistake: Nuclear Man is destroying Metropolis and always, behind him, there is a white truck and a lot of cars. But in one of the shots the cars have vanished and a lot of people appear.
Continuity mistake: After Superman straightens the Russian spaceship, he flies away to save the cosmonaut. In the following wide angle he is flying towards a different direction.
Plot hole: After Nuclear Man slides down the chimney of the Nuclear Plant the lid of the reactor is open and then automatically closes. This whole premise is totally absurd, not only for security reasons, but for logical ones too.
Visible crew/equipment: Lighting screens are reflected on a hotdog seller's glasses when Superman walks to the UN.
Other mistake: Nuclear and Lacy are floating in space, not moving at all, but their hair moves strongly as if in an earthly breeze.
Revealing mistake: After Superman sets the Statue back in place, he lands on the ground and the wall behind wobbles, revealing where the movie was retouched to hide the wires.
Continuity mistake: When Nuclear Man steals the Statue of Liberty, its color keeps swapping between blue and green all the time.
Factual error: While in space, Superman and Nuclear Man's capes are flapping. Since it is a vacuum, there is no air, therefore the capes shouldn't flap. Likewise, on the moon, the dust and dirt are moving too quickly to be in a micro gravity situation.
Revealing mistake: When Nuclear Man blows the first manhole cover up, you can see the small plug-like device that was in the barrel of the ejector device as it flips over.
Other mistake: As Superman flies past the subway train, it's obvious that the train is sitting still, as the view of the tunnel shown it is stationary.
Continuity mistake: When Lois drives to the UN Lacy is not in the car. Half a second later she appears inside.
Continuity mistake: When Superman walks to the UN there's a mounted police man on the right. Shot changes, and he's suddenly on the far left. Shot changes again, and he's now meters ahead, on the left of the UN entrance.
Visible crew/equipment: When Clark watches the subway train leave a stage light is reflected on the carriage.
Continuity mistake: Nuclear man flies over the Russian parade and looks to his right. Then stops and stares in front and shoots fire balls at the tank below. Problem is the parade, tank and everything is taking place behind him (a matte painting). Laserdisc and international extended editions).
Continuity mistake: When Nuclear Man approaches the tornado the clouds and tornado move at normal speed except for the shot of Nuclear in front of the tornado, where it moves in slow motion. Later on, before the family exits the house the tornado moves in slo-mo again. (Laserdisc and international extended editions).
Continuity mistake: When Superman flies to save the girl inside the tornado and the family exits the basement there's a truck by the entrance door filled with hay. Half a second later the truck is gone and reappears behind the family, but now it's empty. (Laserdisc and international extended editions).
Continuity mistake: When Lois visits sick Clark his fringe changes style from brushed to messy to messier between shots, back and forth.
Answer: Lacy had gotten tired of her dad's newspaper, big-city life and decided to move to Smallville because she wanted to experience life at a much slower pace and even decided to live on a farm.