"…When the whole world was falling in on Steve, to find out that the one thing he thought he knew—that his bestfriend was dead—was not even true…it was just a great way to pull the final rug out from under him."
“That’s one of the reasons that this is perhaps more emotional than most comic book movies. Because we always decide, What’s the worst thing that can happen to your character? And it was pretty clear that the worst thing that can happen to our main character was: My best friend, who I thought was dead, is a killing machine.”
- Captain America: The Winter Soldier audio commentary by directors Joe and Anthony Russo and writers Christopher Markus and Stephen McFeely