You know not everything in life that is contagious is bad. Much of it is but there is a lot that is not. Music can be contagious. In this respect I am leaning towards 'catching'. There is a short video clip of a busker on a subway station platform playing Sweet Caroline and the people waiting on the platforms for their trains can't help singing along. It has nothing to do with whether they are fans of Neil Diamond. I dare say that some of them have never heard of Neil Diamond and many others won't care that is a Neil Diamond song. It is just a great song to sing along to and when someone else starts it is so easy to join in. I understand that the Boston Red Sox use this song at their games so maybe it is no surprise people sing it here but I have seen Northern Ireland football fans singing it at a bierkeller in Germany, I have seen 106,000 people singing it at Glastonbury rock music festival in England and I have seen it being sung on a plane by marines flying home from Iraq. It