I love this anime, not only because it has such beautiful animation but because of how real most characters feel.
-This post will have spoilers-
The only two that feels like cliche anime characters are Hazuki Katou and Sapphire Kawashima. Hazuki has moments when she feels real, like when she tells Shuichi Tsukamoto that she likes him and his disappointing awkward response to her.
Those parts really made her feel real but most times, she's reverted back to a cliche foolish character.
In Sound! Euphonium, they show that most of the students are lazy to practice all the time and are only in the club for fun and a little experience. They don't take it serious at all. Only a few of them do.
Every sports anime I've seen will have every single character in the club take the sport very serious. I know even in real life, some high school players take winning and losing very serious. But only some. In other anime they have all the players putting hard work into practice games and official games.
Also, the cliche that there's that one character who's so good, they don't even have to try, can anime stop that cliche already?
With Sound! Euphonium it has Reina Kousaka as the most talented character but she at least is shown practicing a lot on her own. She's not just sitting around bored that she's so much better than everyone without trying. She's actually trying her best every time she's playing.
In sports anime, they want us to believe there are people who are bored with the sport because they are so good but they wont quit the team? In real life, any high school student who's bored out of their minds would quit to find something else that interest them. Or they wont join a club at all.
Any character shown to be so talented should be seen practicing nonstop to keep up their talent. Like Reina.
In a sports anime, all it takes is one bad game for the whole team to get motivation to practice harder than they already have. Losing one game is so life changing for characters it's eye rolling. I understand this might happen to one or two people but the whole team?!
The relationship Kumiko has with Shuichi is my favorite in any anime I've seen before with a male and female being friends.
The relationship Kumiko has with Reina is also really good because it's a close friendship, but they also obviously have feelings for each other. We've seen this before though. Two characters of the same sex seem into each other but nothing happens or talked about. But the way this anime does it is so much more mature than other anime shows have done it.
Just watch it to know what I mean because I'm not good with words.
It bugs me when people ignore bisexuality. I know it's just fictional characters but that's why I said it's a small nitpick.
The relationship Kumiko has with her sister is also another one I like because I can see real siblings acting like them. They are not that close but they don't hate each other.
While other anime will have the siblings be really close with each other (most times in a creepy way). Or they just can't stand to look at each other and are rivals.
(Oh and there's one bullshit episode, it's ep 6 I think. The one where Kumiko wears the costume. Fuck that episode.)