This really is a feature I seem to lack. Standing in a line without at least listening to music makes me really uncomfortable. I don't know where to look, what to do etc.

It is tough. I feel you. Your hands suddenly, are very large; where do they go, or what do they do? But turn the music off. Take a breath. No one is talking about you, nor do you even exist; except as another human body cohabiting, briefly, space with others. Your identity consists of your instantiation in space; you can relax, allow your body-vessel to idle, and crunch through non-present problems. Or just relish the ambient hum. Maybe someone else who is unplugged has made fleeting eye contact, and asked you about the weather.

Haha, exactly :D And the required "Oh no that person looked at me, did I do something weird?"