What goes through some people's heads when they raise their phone volume in public spaces?

It's annoyingly common to see a person, usually more than middle-aged, play a video in obnoxiously loud volume in, say, a bus.

Genuinely, what goes through these people's heads (if anything)? Like, can't they see that there's people around and they're the only ones who are making noise? Are they legitimately immune to embarrassment?