There are few drivers on the road these days considerate enough to try to warn others of the dangerous that may lay ahead. The most common way they try to communicate these warnings is through the headlight flash.
I'm all for the flashing of headlights to warn of danger ahead, it's less jarring than the honking of the horn, it's definitely easier to see than a hand wave (especially at night!) but the problem with the headlight flash is the ambiguity of it all.
I mean, for example, a headlight flash could mean any of the following (or all, if you've got really bad luck): Cops ahead, Deer/large animals ahead, stuff in the road ahead, your headlights aren't on, your high beams are on and they are blinding other drivers, you have the right of way... The list goes on, those are just the things I thought of during the two mile drive from my office to my home this morning after someone flashed their lights at me. Then, someone I know whom I passed coming home called me and said "Hey, I think you have a headlight out."
Well, I never would have thought of that (though I probably would have realized it when I went to go to work tonight, and it was really, really dark.) just because someone flashed their lights at me. Epic Fail.
Don't get me wrong, it was really considerate of the person to try to alert me. Most people wouldn't bother. I wish that there was a less ambiguous way of communicating with other drivers.
Oh well, at least there's only one way to take the middle finger.