I see it all the time, people holding their phones up vertically and taking video. If you ever play that video on your computer or YouTube, it comes out super-stupid looking with the giant bars on the sides. Yes I know that’s how you naturally hold the phone, but please try to think ahead of how this will look later! (Really bad!)
I can’t say anymore about this, but this hilarious video makes it clear:
”Motion pictures, TV’s, and computer screens have always been horizontal. Your EYES are horizontal.”