The climax of HAROLD & MAUDE (1971)--
The end of QUADROPHENIA (1979)--
That both Harold and Jimmy survive, having purged their aesthetic morbidity and empty mod restrictiveness respectively, makes the plagiarism of such a significant plot device all the more galling. (In QUADROPHENIA Jimmy is shown walking away in the opening scene.)
Mind you, that these are both films of significant merit and weight. The level of thievery & borrowing that surely occurs within the dreck manufactured by hollywood hacks could be safely assumed to be staggering.