I'd like to start off my review by thanking my Secret Santa, cosmia, for sending this to me as a suggestion for this holiday season. I've had this show on my want to watch list ever since I heard about it. I can't even say how long it would've been before I watched this, so again, thank you.
Story
I'll start by going over the story. After going to different middle schools, three childhood friends - Tanaka, Kikuchi, and Saginomiya - reuinte as first years at an all-girls high school. All three of them are excited to spend the next few years together, but Tanaka decides to spice up the start of the year by giving all of their classmates nicknames; Kikuchi becomes "Wota" (since she's perceived as an otaku), Saginomiya becomes "Robo" (due to her emotionless attitude), and Tanaka reluctantly becomes "Baka" (because she's not the brightest).
Over the course of the series, Baka, Wota, and Robo meet a variety of other girls and befriend them, including a girl who's convinced she's a half-dragon warrior from another dimension and another girl who's obsessed with occult activities and loves the sight of blood. Many of the later episodes feature girls other than Baka, Wota, and Robo, giving us some insight into their interests, personalities, and how they act with other characters and outside of school. I wasn't sure what I thought of this at first, but I found to be a refreshing change of pace.
Animation
I don't have a whole lot to say about the animation, but I do have a couple of things I'd like to mention. First off, the expressions characters make when they're experiencing strong emotions are over-the-top and often bring a smile to my face. They certainly convey what the character is feeling in that moment. Second, there are select scenes that I did find especially beautiful, such as in the ninth episode where Loli is trying on a variety of clothes and in the final act of the last episode with the sakura trees in the schoolyard. Lastly, I loved to watch the ending and see all of the references to events that took place in previous episodes. The animators certainly could've done something cliche, but they made the effort to do something cute like that, and I appreciate it.
Sound
The sound design was also fairly good. A lot of the music throughout the series is pretty cutsie and upbeat, but they do have some ominous music for more intense scenes here and there. I did think the voice acting was very good, though. My favorite lines were always between Baka, Wota, and Robo because Baka would say something absurd, Wota would freak out about it, and Robo would calmly respond to both of them; I did also find scenes with Baka and Loli equally entertaining.
Speaking of entertaining, this show is friggin' hilarious. I really didn't know what to expect in terms of comedy when I started this, but I think every episode had me laughing out loud at least once. The lines of the characters and their deliveries seemed all too perfect. If you asked me a week ago how funny an anime about high school girls doing random things inside and outside of school would be, I probably would've said moderately; I hope this gives you a good idea of how much I enjoyed the comedy in this show.
Before I get to the characters, I have to talk about the OP; I think I can say that "Wa! Moon! dass! cry!" is already one of my favorite anime OP's, and I only started watching this two days ago. It's got a very unique structure, the lyrics are just as random as the show itself, and the voice actors for Baka, Wota, and Robo sing it. Probably its strongest feature is its chorus; that isn't to say that the verses or prechorus isn't good, but I always seemed to underestimate the chorus when the opening started. Even if this show doesn't sound interesting thus far, give the OP a listen.
Characters
Finally, easily the best part of the whole show, the characters. Every character seems to have some sort of relationship with one another, and they all seem different enough to keep you engaged in them. While I do really like the supporting characters like Loli and Yamai, it's so clear that the core three (Baka, Wota, and Robo) are the most developed, the most interesting, the most entertaining, and the most realistic. They get mad at each other, they make each other laugh, they lift each other up, they bring each other down. If you have a small group of best friends, I wouldn't be surprised if they act like these three do.
However, just as commonxreaction said in his review, you'll either love or hate Baka. When I learned that she was pretty much the main character, I was a bit surprised and disappointed that it wasn't Kikuchi, but I quickly found out why Baka was: she's the glue that holds everyone together. I don't want to fully spoil the ending, but in the last episode, all of the characters come together to help her out. On top of this, she's just one of those people who you love to hate and hate to love. She's probably one of the dumbest, grossest, and most random anime characters I've ever seen, but she certainly stands out, and I think that's why I love her so much.
Conclusion
That statement can be extended to the anime as a whole as well. Wasteful Days of High School Girls may not seem to stand out much at first, and you may continue to think so even after spending some time with it, but there is an equal chance that you may come to think "Why haven't I watched this sooner? Why haven't I heard of this sooner?" And I think I know why that is: this show is like that one kid that you had in your class. You know the one. The one who sat in the back of the room sleeping, talking to his friends about the most random things, and eating food in the middle of class. Maybe they were examining microorganisms on a petri dish, bragging about how they got a 10 on their last test, or gushing over a random Internet artist that only has a small amount of listeners. You probably didn't talk to them when you were in school, but maybe you'll run into them later in life and find something that you'll never forget.