Rational thinking: the wheel bearing on my car needs to be replaced, I can hear it squeaking and I know that's the cause. It's possible that the wheel will literally seize up while driving. I'm in finals prep week, with three trips to and from school before the semester ends and I can give up the car for a few days so my boyfriend can fix it amongst several other equally pressing miscellaneous repairs underway at the moment. I have access to a different vehicle.
Rational decisions: drive the other vehicle, or take mine to backup mechanic and spend an afternoon at the bar next door to his shop studying.
Not me. Kept driving my car, remembering the problem as I pulled out of the driveway every time. I can't defend that choice, it was stupid and potentially dangerous, but I did it. Heck, it barely qualified as a choice - I just remembered, thought "no time, gotta go" and drove on.
Just an example, but one extreme enough to really demonstrate my point. How long, if ever, until newly developing rational thinking routinely translates into rational behavior?