one early first season episode when you knew Cheers was going to be great. Carla and Diane are fighting constantly. Sam forces them to have a ladies night out to bury the hatchet. While sharing drinks Carla tells Diane in confidence she has a secret. A secret that has been eating at her but hasn't told anyone else. She begrudgingly tells Diane that after some partying a few years before she and Sam spent a night together. And her youngest Gino is actually Sam's son. Diane is speechless. Carla makes her promise not to tell anyone.
Next day Diane can't help but share the secret with someone and asks Coach about "little Gino" and Sam her father. Naturally Coach is confused and tells her it doesn't make sense as Gino was born before Carla and Sam knew each other. Naturally Diane is incensed when she finds out it's all a lie and Carla did it just to tick her off and prove that she couldn't keep a secret.
The episode is "Truce or Consequences." Check it out on Hulu. So great.