The Abbot of the Monastery was very strict in his routine.
Each morning, he'd come out of his cell, go into the main
room where all the monks were sitting, and chant "Good
Morning." They would chant back "Good Morning." At the
evening meal, he'd enter the room and sing "Good Evening,"
and they would reply in kind. One morning, though, in
response to his greeting, he distinctly heard one monk sing
"Good Evening." Wondering if his ears were going, he sang
"Good Morning," only to hear the anomalous greeting again.
Looking about the room, he sang "Someone Chanted 'Evening.'"