The fact we are all on the subway for the same basic purpose subliminally provides a democratizing, unifying and human environment.
The person next to you is different than you but is also the same as you. The person is real - not a media concocted persona based on how the person may look, what groups he may belong to or how the media interprets and communicates her assumed motivations.
Digital is great but there are still 24 hours in the day, so the opportunity cost for many of us, including me, is often human interaction. I for one am trying to increase my time with humans on the R train, and decrease my time with personas on social media.