OS X :: Dock Shifts Windows To Side

I set the dock to appear on the left side of my screen with auto-hide turned on and magnification turned off. It's not at full size. I like to keep my windows maximized such that they take up the entire screen. What I've noticed, however, is that when I put the dock on the sides and open a window for any application (Safari, outlook, etc), it'll be shifted to the right just a little bit. This makes part of the desktop background visible, as the application window isn't covering the entire screen. I know it's not a big deal, but it kind of bugs me and I keep on moving the windows back to maximize the screen, but it keeps on shifting to the right. How do I prevent this? I thought it might be because the dock was too big, but really, it's not.