A proctologist had his own practice for thirty years and decided to retire and become a motorcycle mechanic. He went to motorcycle mechanic school and did really well all year long, when the final exam came up the teacher told everyone the 50% of the test would be written and the other 50% would be tearing down and rebuilding a bike. He though he did really well and when he got his test score he got a 200! He went to the teacher and asked how he scored that high. The teacher told him that he aced the written and the tear down/ rebuild and the extra 100 was because he had never seen anybody tear down and rebuild a bike all through the tail pipe!