These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
"Reasonable" apart from wanting to exile anyone he deems "warlike" to Earth and letting the Ghingnham faction do whatever it deems fit to get the Willgame off the moon.
Complete Monster: Gym Ghingnham. He threatens to rape Kihel, kills his own men on the slightest pretext, like when he needs to test a new weapon, or when his subordinates try to assist him in battle (unless it happens to be turning against him), and generally views kills as points on a scorecard rather than, you know, lives ended. When the Dark History is revealed, Gym's immediate thought is that it would be awesome to do it all over again.
Anything with Bruno and Jacop after their Heel-Face Turn, particularly when Jacop tries on Harry's glasses.
In Episode 22, a disguised Harry confronts Loran about his disguise as Laura. When Loran replies that it isn't exactly a disguise, Harry mistakes the reply that Loran means that he likes cross-dressing...
Fran also takes the piss out of the dramatic entrance of the Turn-X by noting that a turned X is still an X.
In the last episode Lily Borjarno finally gets fed up with Guin calling Loran "Laura", and suggests he put on a skirt and chase after Loran. Guin notes that society hasn't progressed to the point where someone wearing a skirt can rule the world. Mere minutes later, he is forced to flee into exile and Lily declares that she will take over control of America Ameria in her skirt.
Darkness-Induced Audience Apathy: The Black History kills every happy ending or advance humans make. Humans make contact with aliens? We have absolutely no explanation for what happened but The Black History means something went terribly wrong. Descendants of your favorite characters? Probably dead. The end of the season and peace at last? Meaningless because of The Black History. And a lot more.
Freud Was Right: Corin Nander's unitard has a very suggestively-designed arrow-and-circle 'male' symbol on the crotch.
Fridge Horror: Minor villain Teteth Helleh gets some humanization just before she dies. 30 episodes later, we see the reason for her humanization (her mother) come out of Hibernation looking for her. Two characters nearby comment that they've heard the name she's calling out for before.
The Reveal about the Black History means that the struggles in every other Gundam series you've watched ended with the Moonlight Butterfly centuries later. It's worse if the series had an idealistic ending, because it means that all their struggles and hope for the future just ended with humanity falling back into devastating wars.
God-Mode Sue: Arguably the Turn A. Arguably because while powerful it still comes across as if a good zerg rush or death of a thousand cuts could do it in. It also helps that its ultimate opponent, the Turn X, is just as powerful.
It Was His Sled: The Reveal that the Black History refers to the events of previous Gundam series was a major plot twist; nowadays, just try to discuss Turn A without it coming up at some point.
Tear Jerker: The absolutely beautiful ending in the final episode on its own, and especially if you've seen the entire series. Here it is for those of you willing to see it. Spoilers abound...it IS the ending.
The funeral of Dylan Heim in episode three. Sochie and the two house servants are absolutely overcome with grief, as is Loran over the death of a nice man who really did nothing to deserve it. To make matters worse, he is one of so many casualties that they have to rush to bury him right away, even before contacting his wife and daughter.
Unfortunate Implications: Calling the history of war the "Black History" is a huge one. Possibly why some translations go with "Dark History" instead.
Vindicated by History: While the series wasn't very successful with its initial ratings, it's over time grown in popularity and is these days seen as one of Tomino's best Gundam works.
What Could Have Been: At one point in the draft of the ending, Dianna was supposed to be showing obvious signs of age. (She ends up using a walking stick, maybe, and sounds a little older in the final version.)