Forgive me using first person here, but when I was a kid I thought Nick and Loretta Tortelli were two of the funniest characters ever on Cheers. It's easy to see why: they're both cartoon characters, the kind of broad stereotypes that dominated the later seasons of the series. Looking back now, they seem a bit too broad.
Nevertheless, it *is* inspired casting. Dan Hedaya has played sleazy characters (and the occasional sympathetic roles) for a variety of directors from The Coen Brothers to Oliver Stone to David Lynch. He looks like he was born with a five o'clock shadow. Jean Kasem is the kind of blonde actress that used to be described as "pneumatic," with a voice channeling Lina Lamont from Singin' In The Rain. Nick has brought Loretta in to make Carla jealous, and Carla enlists Sam to pretend to be her new boyfriend.
There's some nice moments where we get some insight into Sam and Carla's friendship, but this ends up being a fairly inconsequential episode. There is one funny bit near the beginning, when Carla locks herself in Sam's office. Out pops Dr. Paul Kendall, "a licensed psychotherapist specialising in crisis behaviour." The good Dr. Kendall tries to help Carla to no avail in a scene straight out of a Looney Tunes short. Dr. Kendall is pompous, egotistical and incredibly ineffective - not unlike a certain character who will appear in the next season...