Continuity mistake: At the end when Spider-Man dumps the brick wall on the Green Goblin, the wall is still in one piece after it's landed in the long shot, but when the angle changes, the wall's almost destroyed, and the Goblin pushes his hand up through rubble. (01:42:55)
Continuity mistake: During the bridge scene the wire supporting the tram/cable car was obviously anchored on the other end when the Green Goblin was holding it, because the car's suspended on a near horizontal line, with the regular support at one end and the Goblin on the other. All well and good, and even after Spider-Man grabs Mary Jane we see the car drop with the wire still looped through the pulley, both ends visible. In the next shot from above though, the other end of the wire's disappeared, and the car's now just hanging off a single cable which is attached to the top of the car. How'd that happen? (01:38:25)
Visible crew/equipment: When Mary Jane is on the balcony at the Oscorp Festival and the Green Goblin causes part of it to start falling apart, the wires and chords causing the balcony to fall down and pull back up can be seen. (01:07:20)
Revealing mistake: Flash attacks Peter in the school's hallway. We are supposed to witness Peter's incredible speed in one shot, as he dodges a punch in slow motion. Flash's bracelet, however, is motionless. The speed of the punch would throw it back and forth, as it does throughout the rest of the scene. (00:23:50)
Continuity mistake: When MJ kisses Peter in the cemetery, his head is leaning towards his left, and in the next shot, his head is leaning towards his right. (01:53:10)
Continuity mistake: When Peter accidentally flings the tray of food on Flash it hits him on the left shoulder but when Flash stands up the stain temporarily jumps over to his right shoulder. (00:23:19)
Revealing mistake: After rescuing Mary Jane and leaving her at the church, Spider-Man apparently uses a trampoline to jump off the ledge - he jumps up onto something before springing off. Mary Jane then runs forward and clambers around something to get close to the edge. (01:07:40)
Continuity mistake: In the final fight scene between Green Goblin and Spider-Man, the damaged eyepiece over Spider-Man's left eye keeps changing its damage pattern between shots. (01:45:15)
Continuity mistake: When Peter is trying to talk to Mary in the cafeteria you can see behind where he is standing there are numerous people and tables between him and the back wall. Peter then sits down and in the very next shot his table is one table away from the wall behind him. The shot may be lower but is from the same angle as before. (00:21:35)
Revealing mistake: When the Green Goblin attacks J. Jonah Jameson at the office, Spider-Man shows up. Goblin turns his glider to face his nemesis. If you look closely, you can tell that it is a rotating rig, and that the film was sped up. Goblin's body shifts abruptly while he turns, and the fire in the background is moving too quickly to be at normal speed. (01:15:20)
Audio problem: When Mary Jane is about to fall from the balcony and the Green Goblin appears in front of her, we hear him say, "Hello, my dear," but his mouth is not in sync with those words. (01:07:40)
Factual error: In the graduation scene, watch for the giant spiky orange flowers behind Norman Osborn. These are tropical birds of paradise flowers which grow all over California but would never survive in New York. [Confirmation of that: one contributor was taking a studio tour at Sony studios in Culver City, CA on March 26, 2001, and saw the filming of the graduation scene, complete with Tobey and Kirsten zipping by sitting side-by-side in the jump seat of a golf cart.] (00:49:10)
Continuity mistake: When Mary Jane and Peter are talking in the street right after she left the diner, every time a car passes by behind her and then the camera goes to Peter, those cars would mysteriously vanish since you can clearly see that there are no moving vehicles behind him. (00:55:10)
Continuity mistake: In Jameson's office you can see a building across the street through the window, but when Spider-Man is gassed and falls out, a shot from the street shows Spider-Man falling from an extremely high building that has no other buildings near it. (01:14:25)
Continuity mistake: When the building is on fire, you see a fireman (helmet has 57 on it) assisting in getting the residents out of the structure. Take notice that the fireman has an annoying strap hanging down from the top of his helmet. The strap disappears/reappears a few times during the scene. (01:22:05 - 01:22:45)
Continuity mistake: When Peter shoots webs around his room and hits the rocket over, all that is on the nightstand is the cool light bulb lamp, the picture and the Dr. Pepper can. When it flips back to the nightstand again you can see some weird green alarm clock next to the overturned picture. (00:33:15)
Continuity mistake: When Peter is just getting to the science lab at the beginning right after his friend gets out of his fancy car, if you look at the extras walking behind the two, you will see a bright red haired girl walking by, going towards the building, but when the camera focuses on Peter the girl is there again, walking the opposite way on the other side of the huge sidewalk. You see her about 5 times going back and forth to the building. The first few times she's alone, then she's walking with another girl. (00:05:55)
Continuity mistake: When we see Spider-Man protect the armoured car and take out the thieves, we see that Spider-Man throws a robber over his head and the robber hits a wall. The following shot his position has changed lying on the floor. (00:58:35)
Continuity mistake: Near the beginning of the film when we see Peter waking up and reaching for his glasses, in the previous shot he didn't have the blanket on him or over his shoulders, it's in the background on the floor, yet when he reaches for his glasses the blanket is on his shoulders. (00:17:05)
Continuity mistake: In the scene in which Peter and Flash are fighting in the hall, Harry runs up to Mary Jane to see what is happening, seconds later Peter jumps up to avoid Flash's friend charging him from behind. In the shot of Peter flipping in the air, you can see that Harry is no longer standing next to Mary Jane, a girl in a blue sweater is. After Peter lands, the camera cuts back to Mary Jane and Harry is once again by her side. (00:24:25)
Answer: Remember that Green Goblin (Norman Osborne) just found out that Peter Parker is Spider-Man. Aunt May's comment about everyone knows he loves Mary-Jane concerns him because he now realizes that Green Goblin might find/kidnap Mary-Jane just to lure Spider-Man into a fight. This is the basis for the whole reason he can't be with her, as he would be potentially putting her in harm's way all the time if they got together.
Jazetopher