Sometimes I want to be among people, even if I'm not going to interact with them much. This was particularly true during grad school, when I was working almost completely by myself on my own work, most of the time. Doing my work at the local coffee shop was some of the only social outlet I had. Without it, I would have felt even more isolated.

Now that I have a job, I'll often go to coffee shops if I work on the weekend. And, again, it's because doing it by myself, at home, feels very isolating. Even though I like having time to myself late in the evening, it's rare that I want no social interaction during the day. And if I need to get work done during that day, I'll often use a coffee shop.