An angry motorist went back to a garage where he'd purchased an expensive battery for his car six months earlier. "Listen," the motorist grumbled to the owner of the garage, "when I bought that battery you said it would be the last battery my car would ever need. It died after only six months!"
"Sorry," apologized the garage owner. "I didn't think your car would last longer than that."
"Jerkwater" is a railroad term. Until about fifty years ago, most trains were pulled by thirsty steam engines that needed to refill their boilers from water towers next to the tracks. But some towns were so small and inconsequential that they lacked a water tower. When trains stopped in those places, the crew had to find a nearby stream or well and, bucket-brigade style, "jerk" the water to the train. Those little dots on the map became known as jerkwater towns.
