Each interruption you get (colleagues asking you something, chat messages, impromptu meetings, even you catching with the corner of the eye two of your colleagues leaving their tables to grab a coffee) costs at least 15 minutes of your time to get back into a focused (i.e, productive) mental state.
> What's wrong with just putting some headphones on if you want to put your head down and do some deep, quiet work?
I don't know you, so don't try to take it personally, but I'd venture that your always-on generation and the constant expectation of immediate feedback led to most of the younger ones incapable of really deep focus. When 85% of the solutions to our problems is no more than 5 minutes of Googling around, it gets really hard to exercise that part of the brain where we set ourselves to dig through all the layers of abstraction and build a good mental map of the problem to be solved.
When you do get in such a deep state of focus, it is not a problem to be "plain isolating to be in a room all day" because you don't realize the time passing around you. Like reading a good book that you just can't drop until is finished, no one should feel bad for coming out of a 5-6 hour session of deep focus, productive work and "not having connected" during that time.