Bad Qualities
The main problem about the show is that it doesn't have the same charm as the original series. There are barely action scenes or battle scenes, no serious or dramatic moments or character development, it's all just supposed to be comedy.
In addition, it barely stays true to the source material at all. The universe of Teen Titans Go! is a pancake surrounded by a butter wall, for crying out loud!
Attempts at humor are often either rude, disrespectful, or contrived, consisting mostly of extremely low-brow jokes and toiletries, twerking, and gross-out humor. There are dated pop culture references that feel out-of-place because they don’t even need to be there.
The episode "Toddler Titans... Yay!" mostly parodies Dora the Explorer, with Beast Boy's character, Greenie the Clue Dog, parodying Blue from Blue's Clues and its reboot, Blue's Clues & You!
A piece of music in the soundtrack that plays in a few episodes sounds uncannily similar to the theme song of The Loud House, a popular cartoon on Nickelodeon.
There’s some disgusting moments in the show such as the characters eating expired food, Starfire’s early care ritual for Silkie, the Tooth Fairy eating human teeth (as seen in Dignity of Teeth), etc.
Quantity Over Quality: The series now has 7 seasons and over 300+ episodes and counting, meaning it’s lasted longer than the original show, and while it isn’t too much, it will also often jump the shark because of this, and, as stated later in this article, it could have been been cancelled earlier if not for Cartoon Network airing countless reruns of the series.
Clearly, this spin-off only exists just to try desperately to get a cheap laugh out of the audience and for Cartoon Network to try boosting ratings so that newer shows like Mao Mao: Heroes of Pure Heart won't be cancelled.
Another problem was that in 2014-2018, the show took up most of the schedule on Cartoon Network, just because it was pulling in better ratings than other shows.
In late December 2017, the show managed to have an all-episode marathon and is promptly aired on the network's schedule 384 times with Steven Universe thankfully only airing twice this time of said year, probably just to boost ratings among younger children. Even Cartoon Network's schedule said that they were on the naughty list this year and became proud of that.
This could be more proof that this show basically does quantity over quality (As said in WIS #2), as the creators overload this show with bad episodes instead of taking the time to make good ones (Yes, there may be some good episodes, but still). As a result, Cartoon Network milked this show to death
The Flash animation, while not terrible by itself, looks pretty mediocre and choppy-looking compared to the original 2003 show's animation.
On top of that, there are easily noticeable errors in some episodes (e.g. characters' eyes disappearing, frames where someone stands still like a statue, characters switching places from time to time, characters' emotions not matching what they are saying and voice acting pauses).
In one episode, Beast Boy jumps onto Raven’s leg and there's a frame where Beast Boy is still standing.
The animation is worse than usual in some episodes, like "Staring at the Future".
The color scheme is way too bright in some aspects.