Let's start with the comedy because that's the main reason Gintama is so horrible. Gintama is often called "a comedy series without any comedy", and that's very accurate. The "comedy" in Gintama consists of colorful bunch of jokes... at least if our color vision is limited to two as practically every joke is either a) a penis joke or b) IT'S a PRank BrO. Be it a gorilla mistaking someone's dick for a banana or 7 feet long sword ending up inside someone's anal cavity, Gintama has it all. But don't worry. It's all made with self-awareness and 4th wall breaking so it's very funneh even after 700 chapters and 360 episodes. The parody side is really either a) an excuse to write something absolutely terrible and then claim it was made as a joke, or b) references that are so inaccurate and irrelevant that they could be used in E3's pressconference. The banter on the other hand is almost as hideous as seen in the movie Deadpool 2, but thank God not as meta. The comedy is so bad and badly timed that even during the more serious and decent moments, it comes there and completely ruins everything the series accomplishes by inserting some dude there who farts or does something equally lame.
The characters are something that could be decent -- to be frank, if the characters were a separate entity, they could all be said to be of respectable quality -- but the author practically never uses their personalities for their benefit. Almost every single reaction they show is ridiculously, even absurdly overreacted because the author doesn't trust that his characters' personalities alone could carry the content and the jokes he presents. The work is filled with moments where characters just yell some nonsense to each others because apparently, acting like overdramatic clowns is much better than actually creating comedy based to their characteristics. The sentence "it's so damn anime" is pretty much the perfect way to describe how Gintama's cast works. The only character who gets dealt with the respect they deserve, is Zura, and that's not enough.
The art is very clever. At least if we consider edgy 10 year old kids who are vandalizing the town by drawing pictures of genitals on every damn thing they see, clever. When it comes to Gintama, I don't think I have ever seen anyone put so much effort into making every goddamn background object resemble the shape of a penis. Perhaps my favorite part of the art is how often it focuses on puking and blood and assholes and dicks, yet every time these are censored and pixelated so its readers/viewers won't form a trauma because let's face it, most of them are also like 10 years old. It's beyond me how the main content is penis, farts and in generally, dirty jokes, yet they are presented pseudo and aimed for little kids. At least series like South Park went all out with their content and remained loyal to the idea to the very end. Gintama is just censorship aimed for people whose sense of humor was formed in elementary school toilets but never developed it more mature and over the top direction. Gintama is like a person who ages, but never grows up or matures.
As a conclusion: I laughed something like ~50 times during the entire run. Gintama is not a good series. It's characters are pretty much always used as comedy elements, the jokes get old in 50 episodes (starting from 80 because the first 80 don't even have any jokes), the writing is often ruined by stupid "gags" to a point that the good things become less good. Every cringe and downright awful piece of writing is justified by it being a parody. "So you're denying all the good things the show accomplished." Not really, I am just saying that even the worst of things have good sides in them and just like that, I won't be praising Gintama for its achievements.
