Revealing mistake: When the movie ends and Superman grabs Lenny and Lex's car, they both become black and white coloured and semi transparent.
Revealing mistake: Underneath Lenny's car when it flies away in the quarry there's no pipes, no nothing, just a black plank, revealing the car's a cheap prop.
Continuity mistake: When the firemen are grabbing the hose, the black car on the left turns around 180ยบ and changes model between shots. Also, the yellow cab on the right changes positions and model, notice its headlights changing styles between shots.
Visible crew/equipment: When Superman saves the cosmonaut, stage lights are reflected on his visor.
Revealing mistake: When Nuclear Man flies through the ceiling for the first time, the first glass he crashes into is noticeably different than the others surrounding it, revealing it's a prop.
Continuity mistake: When Nuclear Man sees the newspaper, it smooths itself between shots.
Other mistake: When Superman flies next to the subway carriage and Lois spots him and smiles, he is flying in the opposite direction.
Continuity mistake: When Clark hears Lois' cries for help he is by the edge of the subway platform. A frame later he is a meter away.
Continuity mistake: Position of thumb changes when Superman carries the Statue, before he is attacked by Nuclear Man.
Revealing mistake: Same footage used when the Statue of Liberty plummets and when it's lifted up by Superman, though reversed.
Continuity mistake: Pavement swaps from dry to wet when the SWAT van is attacked.
Continuity mistake: Before the cop cars drive backwards and crash, all the cops around the cars disappear.
Revealing mistake: Superman's hands move despite him being frozen in a block of ice.
Revealing mistake: Reversed scene when Nuclear Man exits the volcano: note the white smoke climbing upwards into the crater.
Continuity mistake: Nuclear Man's hair becomes shorter when he approaches to read the newspaper.
Visible crew/equipment: When the SWAT van is lifted up there is a crane reflected on SWAT van.
Continuity mistake: During the Metropolis attack, the sky alternates from cloudy to sunny.
Continuity mistake: Nuclear walks towards the newspaper with Lacy's picture and moves his right arm to grab it. A frame later his arm is still, resting by his side.
Continuity mistake: Before Nuclear Man sees Lacy's picture he flies up and produces a big cloud of smoke, which disappears a frame later from a different angle.
Continuity mistake: Lacy flirts with Clark and places her left hand all along his shoulder. A frame later her hand is close to his neck.
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.