Let us take the Stop sign. It's pretty easy to know what your supposed to do at that big Red Octagon.
So why is it so hard for people to do this? Now, when I come home from class, I take a road that isn't used very often. it has a stop sign at a four way intersection. I don't care that I can see that nobody is coming. I stop. Because that's what the sign is there for! Almost everyone else plows through that right turn at a good 35 km/h, and there have been a few times where I've almost been hit by some idiot who decided that he was going to ignore the stop sign (the North-South part of the intersection has it, while the East-West does not.)
If someone were to hit another car while failing to stop at a stop sign. that's there fault. Thus they are paying to fix my car should they hit me. Risky driving behaviour will eventually result in an accident. So please! Don't drive like an idiot.