Avengers: Endgame - 13 Best Callbacks To The MCU
9. "You're Taking All The Stupid With You"
Just before he goes back into the Quantum Realm for one final trip into the past, Captain America shares a select few goodbyes with some of his closest friends. Among these is a goodbye with none other than Bucky Barnes in which Cap says, "Don't do anything stupid while I'm gone", to which Bucky responds, "How can I? You're taking all the stupid with you."
On its own merit, this is a great final exchange that summarizes the entirety of Cap and Bucky's friendship. But it becomes all the more meaningful because its actually a word-for-word repeat of the lines they say to each other in Captain America: The First Avenger just before Bucky goes off to war, somewhere the small pre-super soldier serum Steve cannot follow.
In that film, it was Bucky emploring Steve not to do anything stupid while he was gone. In Endgame, the lines are reversed. This recontextualization of the lines provides a powerful and poetic end to their relationship, one that sees Steve instead going off to somewhere Bucky cannot follow.