The Biker & The Old Man

This little old man walked into a bar lookin for trouble.  So he sought out the biggest, meanest looking biker, who was sitting at the bar drinking a beer, and he walked up to him and said, "Hey...I saw your grandma last night."  The biker raised his eyebrow and then turned around, taking another swig of beer.  Not satisfied, the old man tapped on his shoulder again.  He said, "I saw your grandma naked last night."  The biker shook his head and took another swig of beer.  Determined, the old man tapped on his shoulder one more time.  He said, "I banged your grandma last night."  With that, the biker slammed his beer on the table, stood up and said, "Damnit Grandpa...go home!"