>For a "hey there" conversation, most teammates have to get up and walk over to someone else... tap them to shake them out of their focus and get them to take their headphones off.

I think it's pretty tough to read if it's okay to interrupt when your teammate is wearing headphones (especially if, as you said, everyone wears them most of the day). Sometimes I'm just wearing headphones to listen to some music while doing something easy and tedious, which would be okay to interrupt. But if I'm diving deep into some system to find a mystery bug, then I'd be annoyed if interrupted.

I'm currently working on a project exploring physical interruptions and would appreciate hearing about your (and other HN users') experiences: https://forms.gle/syL1XrLAauxd57hr7