“Of course I don’t have to do this,” one middle aged man said, carefully cleaning the table with a damp cloth. He put the cloth in a little pouch, sat down beside him. “But look, this table’s clean.” He agreed that the table was clean.
“Usually,” the man said, “I work on alien religions… I catalogue, evaluate, compare. I come up with theories and argue with colleagues here and elsewhere. But the job’s never finished. Always new examples and even the old ones get reevaluated and new people come along and come up with new ideas about what you thought was settled. But,” he slapped the table, “when you clean a table, you clean a table. You feel you’ve done something. It’s an achievement.”
> from Use Of Weapons, by Iain M. Banks