Same. Headphones are my "door". Maybe my co-workers are simply self-aware-enough to not interrupt all the time.
also, as far as interruptions go, acoustic interruptions are only one type of interruption. Your brain is physically wired to pay attention to things in your visual fields - it's physically wired to pay attention to people coming and going, continuously assessing the situation. just because you can function in an open space environment it does not mean that the environment is optimal.
I have a pair of shotgun hearing protection ear muffs next to my bed. I only use them for emergencies when I really need to sleep and neighbors are partying very late. However, putting them on cuts any noise to a mumbling like in the distance.
Not the exact model or make but similar. Not electronic.
https://www.dickssportinggoods.com/p/walkers-game-ear-pro-fo...