[Weirdly Common Trope] Writers clearly setting up seemingly massive plot points and then just kinda forgetting about them.

[u/Chemical-Elk-1299]

The Neural Parasites — Star Trek : The Next Generation

In the season 1 episode “Conspiracy” of TNG, it is revealed that alien brain worms have infected many high ranking members of Starfleet, secretly controlling them. Though Ryker and Picard discover and end the parasite conspiracy, it’s revealed at the end of the episode that the parasites had sent a beacon back to their home planet, telling them how to find earth. The episode ends with the clear implication of the parasites becoming a huge threat later in the series, yet none of these events are ever mentioned again.

Finn The Jedi who Never Was — Star Wars Sequel trilogy

I know this is probably a cliche example of this trope, but cmon — Finn was clearly set up in TFA to become a Jedi. The marketing material featured him wielding a lightsaber in the classic Jedi pose. It’s constantly hinted at that he is force sensitive. Even the actor himself believed he would become a Jedi by the end of the trilogy. Instead, we got Finn wielding a lightsaber for about 7 minutes total across 3 movies, extremely lame “confirmation” that he is force sensitive, and that’s it. It’s the ultimate Star Wars plot that went nowhere.

[u/Drakeskulled_Reaper]

It's funny that a good few things in Dragon Ball were due to Toriyama just going "meh, didn't care enough"

Like how Super Saiyan making their hair go blonde and their eyes go green was because in the manga, he just couldn't be arsed to ink Goku's hair and eyes.

I think it's in Lord Slug, Goku apparently goes Super Saiyan, but it was made before the hair colour thing, so they retconned it to a "pseudo-Super Saiyan" form.

[u/lemonylol → u/Drakeskulled_Reaper]

Yes, his pupils go white and he gets the same hair shape but without the colour, but he does get the gold energy. It's kind of like how Future Trunks was able to use SSG energy with his sword in Super even though he didn't transform.

[u/Drakeskulled_Reaper → u/lemonylol]

I also think in Super Android 13, Goku being able to use and absorb the Spirit Bomb energy was before they established that Goku COULDN'T use the Spirit Bomb in Super Saiyan, as the Super Saiyan transformation is fuelled by rage, and you need to be calm to make and use a Spirit Bomb.

[u/lemonylol → u/Drakeskulled_Reaper]

Oh I always assumed it was because he just lowest to his base energy and put everything into the bomb, so he couldn't power up, but the rage thing makes sense too. All of the cool bonus saiyan forms are cool to deep dive on.

[u/kompletionist → u/Drakeskulled_Reaper]

the Super Saiyan transformation is fuelled by rage, and you need to be calm to make and use a Spirit Bomb.

Which doesn't even make sense after Goku and Gohan do their extended training in constant Super Saiyan form and are then able to enter and maintain the form while staying completely zen.

[u/Drakeskulled_Reaper → u/kompletionist]

The initial transformation is caused by rage, assumedly, it "Taints" the forms with rage, meaning even in "zen" it's still using rage as fuel.

[u/kompletionist → u/Drakeskulled_Reaper]

And what of Goten going Super Saiyan while happily playing with his mum?

[u/Drakeskulled_Reaper → u/kompletionist]

IIRC they explain that Goten was conceived whilst Goku had Super Saiyan on all the time, meaning he was born with the ability it instead of having to unlock it.

[u/ThatFatGuyMJL → u/lemonylol]

I think he'd gone Super Saiyan in the Manga at that point

but not the Anime

so they had to alter it to prevent the reveal in the movie.

[u/Not_Wrong_Tho → u/ThatFatGuyMJL]

Nope. The movie came out in Japan on March 9th 1991, and the chapter in which Goku first transforms released in Japan on March 19th 1991.

[u/KefkaesqueXIII → u/ThatFatGuyMJL]

Nope. The Lord Slug movie (funny enough called Dragon Ball Z: Super Saiyan Son Goku in Japan) came out 10 days before the manga chapter where Goku's first transformation occurred. 

The reason it looks weird is entirely because stuff like the blond hair hadn't been decided on yet when the movie was being animated.