About writing: That Coffee Shop Thing

What's up with all the writing in coffee shops?
I have to admit with full disclosure that I am one of those authors, the kind you see taking up a corner of the cafe with a mug and a plate of nibblies.
Or, you may not see me- I tend to be unobtrusive and wrapped up in my own little world. The coffee shop is a great environment for me because it provides two things: a steady supply of snacks and a convivial atmosphere away from dogs, laundry, TV, and the need to answer the phone.
Most of the time my husband is with me, "getting coffee" is a weekend ritual for us that will never be skipped unless we are away at a convention.
Depending on what cafe we plan to visit will set our schedule. Lately we've been going to Crema since Sam & Zoe's got sold and is getting all corporate and snotty. Crema isn't open on Sundays so we go there on Saturdays. If we haven't anything else planned for the weekend, we still might go over to Sam & Zoe's on Sunday (which is really the best day to go there in general as the awesome Baja Burrito [NOT to be confused with the inferior chain place Baja Fresh!] is also closed on Sundays and there is plenty of parking in the tiny lot they share).
At coffee, notebooks and/or laptops are opened and working commences for as long as the batteries hold out. (I am rather suddenly down to 45 minutes of juice on poor Pixie. *pout* Need new battery STAT!)
Usually we stick to our current works in progress, occasionally stopping for a coffee refill, another scone, or to read a sentence aloud to one another to make sure it sounds good.
The staff get to know us pretty quick, many of them already have copies of A Year and a Day and are usually thrilled to know I am working on my next published book in their cafe.
The ever-present hum of chatter and squeal of espresso machines is comforting and generally if people see that I'm working they tend to leave me alone.
I know there is a massive, writerly stereotype of the sorts of people who work in coffee shops, but unlike a lot of those types, my husband and I try to get read work done and don't care who sees us. It is a really nice break from home and the change of atmosphere is incredibly focusing.
And really, if writers around the world are doing it, there has got to be a reason why.
Now you know mine! ^_^