Yet, why are startups trumpeting these as great places to work? Particularly as an engineer, having a door I can close is essential. (That's why I love working on Fridays, when nearly everyone else works from home.)
The biggest stressor for me in an open office is overhearing personal conversations. It's not the noise that bothers me, but the fact that I hear things I really just feel awkward hearing.
My ideal office is just lots and lots of rooms. Maybe you could do an open office if complete silence were enforced on the floor and all meetings were held in adjourning rooms, but that'll never get buy-in.