Having beaten Obadiah Stane's Iron Monger and revealed that he is Iron Man to the world's media, Tony Stark returns home to his humble mansion to find he's got a visitor: Samuel L Jackson's Nick Fury, who chides him on believing he's the only superhero in the world, and informs him of a plan to kick off the Avengers Initiative.
What It Meant
Back in 2008, this was an incredible statement of intent for the MCU: not only had they kept an A-list cameo for a few seconds of screen-time, they were also mapping out a shared universe to wipe out the memory of decades of mostly bad Marvel movies.
Confusingly, Iron Man pretty much was the only superhero in this universe at the time - since almost all of the other origins happened after it - but the hint ahead to him becoming the centre-piece of the Avengers universe was incredible.
It also meant that for the next 9 years, you'd be forced to sit through the credits of every MCU movie, in fear that you'd miss something important.