I wan't to express, that I disliked Rick and Morty season 3

[Der/die AtheistIn]

Only if you didn't think too hard about it. It's a wacky sci-fi cartoon after all. You could nit-pick the plot of pretty much every episode, but why do that? 

Yes, it is wacky, but it's never been that wacky.

I don't think it was meant to be a joke. Just a way to move the story forward. I still don't really see the problem with it. 

If it's meant to move the plot forward and it's not a joke it has to make sense, not necessarily in the real world, but in the fictional world that it's created.

Yeah, I watched an episode of this years ago. I can't remember anything about it, except that I didn't feel like watching any more of it...

It's fine if you don't like it. As I said, Superjail isn't for everyone. The point I was trying to make is that Superjail understood that if a character just gets out it wouldn't be interesting anymore.

Well, no - the show doesn't acknowledge it. In "South Park" there's a character named Towelie, who's a walking, talking, weed-smoking towel and the show openly mocks him for being a ridiculous and lazy design, meant to sell merchandise. Nothing of the sort happens in "Rick and Morty". Mr Poopybutthole is a one-joke character, that keeps reappearing, despite adding nothing to the story (so far at least). And that's what I find funny about him. Of course, humour is somewhat subjective and I'm sure other people have different reasons. 

It's not bad to use a character just for jokes, but the jokes need to be good. As you said, humor is subjective, but I personally cannot understand how Mr. Poopybutthole's mere existence is funny. I found him funny at first, in his first appearance and in the last episode of season 2. But then in season 3 he once appeared in one of Morty's memories, where he was asking the young boy for his hand in marriage and Morty was crying tears of joy. Morty is underage, the fact that he was asked by a funny looking creature with a silly name doesn't make it funny. Maybe they were just pretending. In that case Morty is a hell of a good actor being able to cry on command. Also, if they were just pretending, why would Rick erase Morty's memory? I don't see why Rick would have anything against an innocent role play and also no reason why Morty and Mr. Poopybutthole would keep it a secret. And if they were just role playing, why not tell the audience directly? Are the creators going for pure shock value? Mr Poopybutthole appears once again in the last episode of season 3, where he just says that he went back to school and then made a family. I don't find it funny and the story is so simple and adds nothing to the main plot that it could've been taken out entirely.

Then tell me - what does Mr Poopybutthole add to the mix?

That was the idea, he doesn't add anything new to the mix. If they made a joke about Mr Poopybutthole and his girlfriend looking identical, it would've worked. Maybe if someone mistook her for him in drag or something like that.

Maybe. Or maybe not. But the show's been renewed for another 70 episodes, so who knows what the writers will do with the character.

Well, I found your joke about trinity pretty funny, it would be hard not to make it sound funny. Also, yeah, we don't know what the show will bring us in the future.