I've decided to do a quick heads-up whenever I get honked at on the road. Today, I was riding along to pick up my daughter from school when the Trail-a-Bike chain came off. I stopped, put it back on, then made sure there was no traffic, then pulled out into the lane and went on my way.
A few seconds later, a car drives up behind me and honks. I'm taking the lane on a lane that's not wide enough to share, and I'm about to make a left turn. So, since the car behind me seems to think there's some imminent danger (which is the only legal use of the horn in MD), I dutifully slow down, I carefully take in my surroundings, I make sure that I'm controlling the lane properly, then, seeing no problem, I signal and make my left turn very slowly and carefully. I still have no idea what the danger was, but thanks to the driver's warning, I was able to proceed at about 6mph - slow enough to avoid any potential problem.
The driver ended up being a few seconds later on his commute than he would have been if he hadn't honked, but at least he has the satisfaction of knowing that his use of the horn helped me avoid whatever imminent danger was threatening me.
It's really nice to see that some motorists are unconcerned with the speed of their commute. So many people are in a rush these days, so it's nice to encounter the occasional driver who is willing to sacrifice speed in favor of my safety.
Some might think that the driver was honking in an effort to get me out of his way. I think that's a very cynical attitude. Some folks just want to be helpful. :)