An old guy who'd spent his whole life as a recluse in the desert goes to visit a friend. He'd never seen a train in his life, but on his way he happens upon a railroad track. Standing alongside the track, wondering what the heck it was, he hears a loud whistle. Looking around, he sees a train bearing down on him like something out of the Apocalypse. The train just nudges him a glancing blow, but it still flips him into an arroyo, where his head smacks up against a rock and knocks him colder'n a witch's heart.
A while later he gets up, tenderly feeling the bump on his head and shrugging off the dust, and continues onto his friend's house, the whole time wondering what the devil that big darn thing was that nearly killed him.
His friend greets him, puts on a kettle of tea, and they start swapping old lies. A few minutes later, the tea kettle starts whistling like crazy on the stove and the hermit jumps up in a panic, grabs a chair and pounds the whistling tea kettle flatter'n a pancake.
Amazed, his friend asks, "What the hell did you do that for?"
The hermit says, "Man, those suckers're dangerous. You gotta kill 'em when they're small!"