Once upon a time, before Satan became the superstar demon he is today, he had to do grunt work like any other demon. One time he signed up for a simple job: the Room of 1,000 Demons. The Room of 1,000 Demons stood right before the Door of Enlightenment, in a great Labyrinth in Tibet. The demons served as guardians to prevent anyone from entering the Door, but they were forbidden from using violence.
One day an aspiring adventurer made it all the way through the Labyrinth, and entered the Room. 999 demons immediately began to assail him with all his worst fears. They embodied the bully who had stolen his lunch money, the father who had beaten him, his fears of sexual inadequacy, his fear of dying, and tigers, dragons, and monsters. But one demon did no such thing: Satan.
Instead, Satan cosied up to the aspiring adventurer and told him, in a kind and friendly voice, "It's not your fault if you give up. Look at all these demons! Nobody could have seen this coming. You got farther than anybody else before." Satan fed the adventurer excuse after excuse. "You could have done it when you were younger, but nobody would blame a guy your age for giving up. You could have done it if you had gotten some help, but nobody was here to help you! It's not your fault." The adventurer summoned all his courage whenever one of the other demons presented him with a fear to terrify him, but when Satan offered him an excuse, the adventurer listened.
Eventually, Satan came up with the perfect excuse. The adventurer thanked Satan profusely for clearing everything up for him, and ran out of that room, never to be seen again. He spent his life telling everybody who would listen - which was not very many people - that he had almost attained Enlightenment, but it wasn't his fault that he didn't go all the way. And Satan got an immediate promotion, being placed in charge of the Room of 1,000 Demons. Satan ordered everyone to use his technique, and soon the Room of 1,000 Demons became the Room of 1,000 Excuses. After that, thousands of years went by before any adventurer attained Enlightenment.
based on an idea I stole from here