Here’s why: No one’s going to try to strike up a conversation with me if I’m zoned out listening to music! Besides, it makes you a better target for muggers.
When I stopped listening to music on the train, suddenly I noticed how annoying it is when attractive guys have earbuds in. They might check me out and smile at me, but to talk to me, they have to take the earbuds out (which makes for a slightly less natural pick-up attempt). So they don’t talk to me. Worse would be if they were to keep one earbud in as they talked. Nothing says “I’m not giving you my full attention” like kind of listening to music. And if I were the one listening to music, I doubt they’d even try to get my attention. What are they going to do, tap on my shoulder? Yell? That would be intrusive.
I’ve noticed that more guys check me out when I’m reading a book. Good excuse to get more reading done!