Missouri pedestrians harassed by drivers, too

In a completely unrelated article about a 76-mile walk around Lake Washington, there is this gem:

Novelist Jonathan Franzen, who calls himself a "recreational walker," writes that in recent years, walking in places such as suburban St. Louis and Denver, "a not negligible percentage of the men speeding by me in their cars or sport-utility vehicles feel moved to yell obscenities at me."

I've experienced this as a pedestrian in the Kansas City area, too. I can understand, to a degree, why some motorists might get upset about a slow-moving vehicle ahead of them in the lane (a topic we've recently covered at length on MoBikeFed News).

But why in the world do they feel compelled to holler and honk at some harmless person who's walking alongside the road?

If anyone can explain this to me, I would appreciate it . . .