Warning: Contains Spoilers

Minor, not-really-a-spoiler for Guardians of the Galaxy (but really, it's been around 5 years now), and an actual spoiler for Avengers: Endgame.

At the beginning of Guardians of the Galaxy, Peter Quill is stealing a mysterious orb from a seemingly abandoned planet. He puts on his walkman and dances his way through the landscape to "Come and Get Your Love".

In Avengers: Endgame, they go back in time to this spot (to steal the same item), and they watch Peter dance through the landscape. Except that he's wearing a walkman, so this time only he (and not his audience) can hear the music. And it looks really odd and funny to watch him dance without music.

I think about this sometimes when I'm at work. I use a headset to listen to music on the computer (it's easier to pull it off if someone walks in than to find the right tab to turn off the music). And sometimes I sing to the music, and sometimes I'm enjoying the music a lot, and then I think: this would look and sound really odd to anyone who can't hear the music. Watching that scene in Endgame just confirmed what I had wondered.