If there's one thing the MCU does well, it's the amount of detail put into every frame in every film. Nothing is done by accident, and everything means something, which is understandable, given the near-century of comic book history backing up those films. Even minor characters or those who barely get any screentime are often the subjects of interesting details most viewers probably never notice.
One Of Peter's Teachers Has A Direct Connection To Bruce Banner
From Redditor u/airpod4840:
The college student in the Incredible Hulk (2008) is also Peter Parker’s teacher in Spider-Man: Homecoming (2017).Cool detail?
Heimdall's Eyes Prove He's Always Watching Thor
From Redditor u/DavidtheSquidd:
In Thor (2011), the reflection on Heimdall’s eye is the previous shot, meaning he was watching Thor the whole time.Cool detail?
Korg's Lethargy Is Showing In 'Endgame' Via Some Moss
From Redditor u/thedrizzle126:
In Avengers: Endgame (2019), Korg shows signs of moss growth due to the nature of his and Thor's lazy lifestyle.Cool detail?
Peter's Principal Is The Descendent Of Jim Morita From Cap's Howling Commandos
From Redditor u/margiegogo:
Peter's principal is the grandson of Jim Morita, one of Captain America's Howling Commandos. You can see his army portrait, dog tags, and medals on the wall behind his desk.Cool detail?