I was an R2 doing a mock oral exam with my senior, a third year resident who I knew was going into gastroenterology at the end of the month. The patient was a sweet elderly lady who had difficulty giving her complete history because she was very short of breath. The exam was fairly simple, an obvious case of congestive heart failure. A snap right? Should have been, but there was always the tricky question of that third heart sound, the S3. I had heard of the mythical entity, since the earliest days of medical school. During our first bedside lessons in second year we had a cardiologist who patiently let us all listen to the 'best' S3 he had heard in ages. We all listened intently, trying our hardest to parcel out that little lub or dub or whatever was supposed to be there. After we had all had a turn he asked me if I had heard it. Perhaps foolishly, I was after all only in second year, I admitted that I had not, even though it was the best he had heard in ages. Perhaps stiffened by my admission, every one of the six students admitted the same. The cardiologist looked at us with something between contempt and disgust and said, "what are you all bloody deaf?" He told us to listen again and promptly left as we fiddled with our stethoscopes. I then knew that the S3 must exist.