Why would it matter where I sit? Well normally it doesn't.
Believe me, I'm not one of those who assumes that I can choose any table I like when I step into a restaurant early and there seem to be lots of empty places. I know it would be great if the two of us could sit at that lovely round top in the window that's laid up for 6 but that's not going to happen - or if it does, I doubt this restaurant will be here in a year! Whether you like it or not restaurants have a finite number of tables and they need to 'turn' them if they're going to survive.
Just occasionally though I have to say something. It happened a few days back when I went to quite a casual Brasserie for lunch where they don't accept reservations. Somehow I ended up in what felt like their broom closet. I was squashed against a pillar, close to the bar, that blocked my view of the 5 or 6 empty (2 top) tables by the windows. A foot to my right was one of only two other customers engaged in a fun relationship with her I-pod. Meanwhile over my left shoulder I could feel the tickle of what turned out to be the dining out section of the NYT as my fellow diner turned the page. This gentleman, perched on a stool at the bar stool, was none too happy when I swatted his newspaper a couple of times, suspecting a flying insect!
So, I asked if I could move to one of the tables in the window. Of course I was way too distracted watching the waiter seat the next few groups of people to take advantage of my window view, and I couldn't help noticing that the next 2 tables also both asked to be moved! When this happens I normally pride myself in being able to understand what's going on, but this one got me - either the host was just having a bad day or more likely (s)he'd been told to fill up someone's section.