It's a Good Life written by Jerome Bixby, narrated by Edward E. French

The boy must never be exposed to anything he finds unpleasant, or terrible things will happen to those who express even the slightest negativity. Everyone in the village has learned to say, “It's a good day” even though it is a terrible, unpredictable day that is always at the mercy of 3 year old Anthony and his slightest whim.