To me, there's something slightly numbing to the part of my brain that craves distraction when I'm surrounded by other people going about life like normal--be it the workers cleaning tables, a first date or friends meeting, or the steady stream of people ordering. I also get a similar numbing feeling when vacuuming or showering that allows me to focus conceptually on a hard problem.

And oftentimes it's the novelty of a place that helps inspire some creativity when it comes to writing.

As others have pointed out, it's hard to shut out conversation from coworkers especially if you don't know if they are talking about work related to you. But when you're in public, you know those conversations don't pertain to you and you can feel no back-of-the-mind guilt about shutting them out (which, as an introvert worrying about others' thoughts, _is_ an issue).