John and Bob were two of the bitterest golf rivals at the club. Neither man trusted the others arithmetic. One day they were playing a heated match and watching each other like hawks.  

After holing out on the fourth green and marking his six on the scorecard, John asked Bob, "What'd you have?" Bob went through the motions of mentally counting up. "Six!" he said and then hastily corrected himself. "No--a five."  

Calmly John marked the scorecard, saying out loud "Eight!"  

"Eight?" Bob said, "I couldn't have had eight."  

John said, "Nope, you claimed six, then changed it to five. But actually you had seven."  

"Then why did you mark down eight?" asked Bob.  

John told him, "One stroke penalty, for improving your LIE."