This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Spider-Man 3
This troper had been given explicit spoilers for Spider-Man 3 concerning Harry's death, and she still cried the first time she saw it. And all but two times since.
"I should never have hurt you. Said those things." "None of that matters Peter. You're my friend....." "Best friend." *Sniff!*
Say what you will about 3, but the scene of Sandman getting up in the silo gets me EVERY time. If the shot of him trying to grasp his daughter's locket doesn't do it, it's the music in the scene.
Similarly, the scene where he simply... blows away in the wind makes for a rather sad and touching moment.
The flashback of Ben Parker's death. Especially when we find out that it was an Accidental Murder.
The third movie has the scene where Peter hits Mary Jane in his symbiote induced rage and his My God, What Have I Done? reaction.
Peter and Harry, former friends, at each other's throats. As well as when Harry shields Peter with his body and they make up finally at Harry's death scene.
The 3rd movie in which Aunt May consoles her nephew after his recent downward spiral due to his usage of the symbiote suit and tells Peter to forgive himself and that she believes that he will set things right again.
Peter losing his temper with his landlord who has asked him about his overdue rent. The landlord is clearly crushed, and slowly says that Peter's a good boy, and clearly something is wrong for him to be acting like this.
It's a bit depressing seeing how head over heels Ursula is for Peter, especially during his symbionts-induced craze. She's barely able to contain herself around him and is lapping up all of his attention, baking him cookies and feeding him. And Peter doesn't actually have feelings for her.
Not a part of the movie itself, but rather the DVD release. The commentary track ends with the cast hoping that they get to make another movie. Ouch.