This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Cinema Paradiso
Salvatore seeing the spliced up film of all of the kisses he and Alfredo had to cut out.
When Alfredo tells Salvatore to move away from their village, and to never look back, visit, or even think of them again.
Made especially Bitter Sweet in the extended version, when you find out that the reason Salvatore and Elena didn't get together was because Alfredo, like a father to Salvatore, told Elena that the only way Salvatore can live his dreams is if Elena never sees him again!
Young Salvatore shouting "Aiuto!" ("Help!") while carrying an unconscious Alfredo as the old cinema burns up around them.