Eraser country does not allow certain memories. If it is an ugly incident the eraser officer strikes it through – delete. The delete constitution defines what shall be forgotten. A murder case, a bad taste meal, an argument between neighbours, a sad moment. The mission of the officer is to make sure everyone lives ever happy after.
But of course, the citizens do not have brains. Together with any sad or ugly memories deleted, gone the mind power to think and reflect.