Those "regional" planes can be a hoot. I have a friend who travels regularly from Pittsburgh to Allentown -- usually on a Saab. I never flew on a Saab, but my friend says the passengers have to be evenly distributed around the plane to keep it balanced. First time I heard that, I thought it was the funniest thing, but apparently, it's necessary on these small planes. In fact, nowadays, my friend says no one on her flight sits where they are assigned, and there are some flights where the passengers don't even get seat assignments. Since my friend is accustomed to this "balancing" maneuver now, she just instinctively heads for somewhere in the middle of the plane. Fortunately for my friend, the trip is short and she says often there are empty seats; so she tries to pick a "two seat" row where no one would be sitting next to her so she has an empty seat to spread out a little.
The slightly bigger Embraers aren't all that bad. THe little Saabs sucks though.