My favorite part of Welcome Back Kotter was during the short segments, either leading in to the show or at the end, when Gabe was telling a story/joke to Mrs. K. It was just the two of them in the apartment together. Obviously it was written and rehearsed and they were actors, but when Kaplan delivered the punchline, and she would laugh, it seemed very sweet and charming. As a teenager, that's how I imagined a great marriage would be.