I agree!It's not my "favorite" episode, but I think the "perfect" Star Trek episode is "The Corbomite Maneuver."
Despite the fact that most Star Trek episodes are rescue missions, colony check-ups, police actions, ferrying missions, intergalactic espionage, space wars, etc..."The Corbomite Maneuver" actually has THE premise that Star Trek is supposedly built around, and the actions / behaviors / attitudes of the characters, particularly Kirk, are highly representative of the show's foundational premise.