It seems he was unaware that after finishing his cup he should put that accursed teaspoon into it, to show that he had had enough; thus good manners left his hostess no choice but to pour him another.
原來，他在每次喝完後，不知道該把那隻要命的茶匙放進杯裡以示到此為止，女主人只好依禮再添。