Guardians of the Galaxy 2

Guardians of the Galaxy 2 starts, it's dark and the theater had quieted. The year 1980 popped onto the screen and the song "Brandy" started to play.
Me, whispering: This song is from 1974.
Austin: Shhh.
Me: It was number one in late July.
Austin, ignoring me.
Me: Do you know how I know that?
Austin: Shut up.
After the movie was over and the very last credit had rolled.
Me: I'm sorry for talking during the movie.
Austin: It's all right.
Me: I just really hate continuity errors.
Austin: It wasn't an error. They said the year was 1980, not the song.
Me: I get why they picked the song. Thematically, it fit. They should have done better at having a time appropriate song to match.
Austin: They couldn't fill the show with all 80's music.
Me: They didn't have to fill it, just the opening part where they had the year.