One day a man was walking to a nearby town across some very rough terrain and managed to stumble into a deep pit with extremely steep sides. It took him four hours to finally clamber out.
Some months later he was travelling the same route and because he was daydreaming he contrived to fall into the same pit again. This time, however, armed with some recollection of where the best various hand and foot holds were, he managed to get out in little more than an hour.
The following year he chanced to be going that way again. He remembered that he needed to take care. Nevertheless, he still managed to miss his footing at the crucial point and yes found himself stuck in the same pit once again. But this time he was out again in fifteen minutes.
The next time he had to go to that town he took another route.