This lack of intelligence usually occurs at intersection where there are multiple turning lanes, such as the diagram shown to the left. As you can see, the driver in the rightmost turning lane stays to the right, and winds up in the rightmost lane on the cross street. Unfortunately, what happens far too often is that the idiot on the right cuts you off and turns into the left lane on the cross street. It has happened to me so frequently that I now EXPECT it to happen every time I enter one of these situations.
It also happens on simple right-and-left turns, which really pisses me off. If you check the diagram to the right, the concept of a right turn is pretty easy to digest. However, some people feel as though they can turn right, and then proceed to drift into the lanes on the left, completely ignoring the fact that there will either be cars turning left into that lane, or that traffic is coming down that cross street in the far lanes.
As I type this, I find that this situation is a lot harder to explain in words than I anticipated. I'm hoping that you'll understand what I'm trying to portray, and you'll likely realize that you have also encountered idiots like these.
I'm considering installing a GoPro camera in my car...this way I can show you actual footage of asshat Calgary motorists doing what they do. Stay tuned for that!