Star Trek: The Next Generation, Series 1, Episode 20.
First broadcast on Monday 21 March 1988

Long before the invention of Ronald D Moore, the Klingons were simple souls who enjoyed brownface, poisoning grain, making lists of rules, and planting a bomb on the bridge of the Enterprise. But by 2364, the next generation of Klingons had embraced the wave of liberalism sweeping across the galaxy, all except for a few holdouts who refused to read the series bible and decided they would pass their time yelling and pointing guns at the warp core instead.