TNG - Allegiance (Season 3)

Allegiance is a "Picard" episode, Aliens abduct Picard to a "Prison Cell" with 3 other Aliens, and replace him a fake Picard. The Crew notice that fake Picard is behaving strangely and when he attempts to destroy the ship, they mutiny. Meanwhile, Picard finally figures out that he's not being held in Prison Cell but is part of a Laboratory Experiment.  When he refuses to play along - the whole thing stops. The episode ends on an upnote, as the curious race that "just wanted to see what leadership is all about" is given a taste of their own medicine.

While enjoyable, the episode points out the difference between TNG and TOS Star Trek. In this TNG episode, "evil Picard" isn't evil at all. He's just an alien fake trying to observe how the crew behaves to different styles of Leadership. And there's no real danger, no action, no fisticuffs, and its all settled by a few words. There are no sharp words among the crew. They all agree that Picard is acting weird, and when Ryker decides to relieve Picard, they all support him.

TOS would've been much more dramatic. And you would've had conflict between the crew: Can Kirk be relieved or not? Spock v. McCoy no doubt. And Kirk would've karate chopped 2 or 3 people trying to get out of the prison cell. And the Aliens would've been much more dangerous/malevolent.

 

TNG is more "adult" but also more boring.