I've experienced this spaciness a lot, and it was at its worst when I was in my teens/early 20s. I think it has to do with wearing down the capacity to interact with other people. Having to explain myself especially makes me tired, and having all the attention focused on me for more than 1/2 hour makes me want to fall asleep! Even now, I need a break from people if I start to act spacy, but after a day or so I'm good as new.
When I'm working, having people around focusing their attention on me slows me down a lot. If left by myself, I can work very quickly, using methods I make up on the spot, which I don't have to explain to anyone. If there are other people around, part of my thought process is devoted to "How am I going to explain how I'm doing this and that I'm doing it right?" In the end, it's the result that matters, and as long as they're happy with that, who cares how I got there?
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A boy and his dog can go walking
A boy and his dog sometimes talk to each other
A boy and a dog can be happy sitting down in the woods on a log
But a dog knows his boy can go wrong