The appropriate response to a honking car is a raised middle finger.
I don’t greet people that way… although I used to, many years ago. Unfortunately, a honking car still provokes that sort of knee-jerk (or finger-jerk) reaction in me that I find I still have to suppress, because it doesn’t happen often enough for me to have completely unlearned it.
But it still happens. Happened today, actually. Why? Well, for some idiotic reason, when people drive past someone they recognize, they honk at them.
Now, the car horn is there for only two legitimate reasons: (1) to warn someone or something that your car is on the verge of hitting it, or they are on the verge of hitting you; (2) to remind the daydreaming driver in front of you that the light is green.
Some would add a third—to tell your date, who’s still inside the house, that you’ve arrived—but that’s just rude, and in my father’s neighborhood it’s a behavior that will guarantee Dad will come out of his house to correct you, bringing a camera in case he has to prove to the police you were hostile. But let’s not get into Dad’s hobbies right now.
In general, using your horn for any other reason than the two legitimate ones is a form of rudeness. That’s why the one-digit salute. And it’s very tempting to respond that way.
Consider it from my point of view: When I get honked at, it’s usually because someone sees me walking. I am a pedestrian; I walk just about everywhere. When you’re driving past me at 40 miles per hour, I haven’t necessarily seen into your car to know who you are. You could be some psycho for all I know. I am also not insulated from the loud, obnoxious sound by being in a car. I get to hear the horn full blast, coming directly at me—sometimes at my back, because I was recognized from behind and didn’t have the opportunity to recognize you first. Sometimes I’m listening to my iPod; sometimes I’m thinking, or praying, and I just had my train of thought firebombed by a car horn.
And why on earth does it matter that you’ve recognized me anyway? So you recognized a pedestrian. Big freakin’ deal. I recognize lots of people. I don't blast an air horn at them to say hi. I wave. Wave, you noisy bastards.