I finally cussed someone out for not using headphones
I've had it happen twice on an actual flight. The best was on a flight to Philadelphia where they verbally eviscerated the guy who didn't realize he was in his Bluetooth.
So today, I was in Dallas, on the train with a surley to be missed flight, and all of a sudden the Spanish speaking reals started. I just fucking let loose: "HEY! NOBODY WANTS TO HEAR YOUR SHIT!"
She looked mortified. The girl next to her looked like she wanted her boyfriends to say something. Nobody did anything but her turning it down.