The Irishman
This has to be one of my favourite endings of all time. Im not rewatching this anytime soon though because this movie is almost 4 hours long so for me it takes like 5 hours to watch it in one sitting. Even though its painfully long though its needed to create such a good ending. You get 3 hours of fun mafia stuff, but in the end you are left with an sad old man reminiscing on the good old days. His friends are all dead and his family hates him. Its kinda sad to watch