Insane American middle-aged bicyclists

So, I was biking on the Struble trail yesterday, a nice little trail along the banks of the Brandywine creek, minding my own business, when I spot a couple of middle-aged American bicyclists in front of me, one perceptibly older than the other, both doing a leisurely pace. I was on a faster rhythm, so I biked up to them, announced "On your left" as is customary, and passed them. Well, I dont know if the idea of a brownish colored young prick from a strange country passing two native sons of the soil was distasteful to them or what, but the next thing I know, after having biked a couple hundred feet, the two, having shed their leisurely pace, go barrelling past me. One of them, the younger one, feeling the need to impress me with his bicycling prowess, started doing a kind of zigzag jig on his bike with the other guy, presumably an older relation of some kind, looking on proudly. "Look at my boy", he must have been thinking to himself, just a split second before his boy zigged a bit too much, zagged all over the trail and finally collapsed in a humongous mound of red, white and blue flesh and fabric. Now, I am as big a fan of watching other people take a fall as the next guy, but I am not vindictive. So, quietly, with a straight face, I moved on, allowing the two comics to pick up the pieces of their lives and shattered pride.