For me it's Shoujo Kageki Revue Starlight. And the anime is honestly not even that bad; if you're willing to ignore the silly ending. It just could have been SO much better.
I wasn't a theater kid and I never knew any growing up, but I think even I could write a better story about girls who attend an elite acting school by day and a battle royale for a mysterious power by night.
For some reason, even though it's the exact same group of girls involved in both activities, the writing just refuses to connect them in any meaningful way.
"Win the Revue and become the Top Star, the best actress ever!" ---> Actually, being the Top Star has nothing to do with acting; you just get a wish. This isn't a 'twist' or anything, it's just something the writers overlooked. O_o
"Sing and dance upon the stage, and show off your 'brilliance'!" ---> Actually, you win in the Revue by cutting off your opponent's "cape"-- which is a really cool and dramatic visual, complete with its own unique sound effect, but it STILL has nothing to do with acting. During the Revues you don't even get the sense that the girls are trying to outdo each other in showmanship; they're basically just fighting.
"Oh no: being the Top Star means you steal everyone else's 'brilliance'!" ---> Actually, there's been a Top Star in play the whole time, and none of the other characters seem any less 'brilliant' (and the Top Star herself is basically a background mom-friend before she becomes a twist villain...no one pays any special attention to her). There go the only stakes in the show. O_o O_o O_o
And despite all those plot holes, the Revue is kind of the only part of the show worth watching.
The real-world parts that are supposed to be the most relevant (the acting classes, the Starlight play the entire story revolves around) are actually the most ignored. T_T It's as if the people writing the anime have no real interest in theater, but hope that if they make the characters talk about it enough it'll seem important.
Case in point: Starlight itself is the most dull-looking play I've ever seen. I mean, it doesn't look dull; the set design is fantastic (by the way, there's an entire half of the school devoted to non-actors, people who do lighting, sets, costumes...they are ALL unimportant background characters who literally only exist for worldbuilding).
But Starlight isn't tableau vivant, it's supposed to be a play. The actresses are supposed to do more than stand around and look cute while yelling out exposition in monotone voices (they're really going to a special school to give a kindergarten-level performance??). But nope, that's all we get. =/ And this is what we're supposed to be concerned about, this is the play so beloved by one of the characters that it damn near drives her insane. And it's just...so boring.
The anime is very pretty, and its characters are cute (and the music is phenomenal~), and it plays to those strengths well, but beyond that it's just devoid of substance for no real reason. There are plenty of elements in it that could actually be suspenseful and interesting, but they remain undeveloped in favor of cheap 'dark magical girl' tropes. Seriously, it feels like a show that secretly, desperately wants what Madoka Magica has, when it would be much better off focusing on its own premise.
