I can't even anymore...
So you go and sit next to that idiot, looking over their shoulder at whatever show they're watching, or if it's music, just dance weirdly in front of them, maintaining disturbing eye contact.
I saw a post where someone on the bus was having a very loud speakerphone conversation. Fed up, the person behind them leaned forward and moaned, "Mmmm, put down the phone and come back to bed, sweetie!" Loud talker very quickly realized they could, in fact, have a quieter, private phone call after all.
Nothing like sitting next to somebody who's decided that the public space you're in is the best time to have an argument with their credit card company.