'Late Show' Recap: David Letterman Says Goodbye to Steve Martin

Rolling Stone is recapping every Late Show With David Letterman until the finale on May 20. The usual writer is off for a few days, so I'll be filling in. Here's my take on Friday's episode, which featured Steve Martin, "Will the Circle Be Unbroken?" and an encore presentation of a classic Steve & Dave bit. Why wasn't the night more fun than it was? Here's my take.