Given the overwhelming surplus of articles about David Letterman’s retirement, career and final show tonight, there barely needs to be anything said here. Bill Murray was the guest on last night’s penultimate show, which is fitting, as he was the first guest on Letterman’s first NBC show in 1982. They antagonized each other, watched a panda video and then Murray performed Olivia Newton-John’s “Physical,” which is basically everything you need for good television.