It isn't all about you. Let me say that again: it isn't all about you. I don't care how good of a driver you are but your headlights purpose is not solely for you to see where you are going at midnight. Your headlights help other people see YOU! So if it is not sunny and bright outside, turning your headlights on (and subsequently also your running lights) makes you visible. The people driving around you in the rain, snow, dust storm, whatever, can now see you coming from the other direction or merging like a moron (cough, Colorado drivers, cough).

Why do you not do it with the lights on!?

1. Because I'm Being Defensive
• Defensive driving means you are limiting your thinking to reactive. Sure, it is smart to be aware of the other drivers around you but where you are will change how they drive. If you are more visible to the offensive drivers right on your bumper then they may give you another extra few inches.
2. Because I'm Being Selfish
• Maybe when you got in your car you flipped your light on and off to see if it did anything. Or maybe your car is soo smart it is supposed to "take care of itself". Do you think you are the only one on the road? No... otherwise you wouldn't be sitting in traffic right now. Help the traffic help you and turn your lights on for others on the road with you.
3. Because I'm Oblivious
• The worst! You are so involved in what is going on inside the car (music, cell phone, heater, whatever) you just don't even realize that you should turn your wipers or headlights on. Why do you think that truck cut you off? They must want you to start your day off with the wrong foot forward. Uh, no... open your eyes and please just drive!