i can't explain the appeal, but i worked out of a coffee shop for 3 months a couple of years ago and it was definitely there for me.

your self control theory might be a part of it although i don't recall doing any less random surfing. and believe me i would notice if some environment helped me tone down my random surfing.

i think just being around people, even (maybe especially) if they have no bearing on my activity, is comforting and helps me focus. at the risk of concocting one of those questionable evolutionary psychology theories, most of our ancestors probably didn't do a lot of productive work in complete isolation?