Alright, here are my honest opinions! Please note that I will be a bit blunt, because I want to be true here. No hard feelings! I'm just being honest about my thoughts, so please don't feel hurt.
-As much as I absolutely hate to admit it, the Anime fandom can get just as toxic as the K-pop fandom. When I say "fandom", I am not implying to all fans, I'm simply pinpointing the toxic and obnoxious ones. Take Haikyu!!, Free!, and Yuri on Ice as examples. They're three of my many favorite anime shows. I wouldn't call myself a toxic otaku; I respect everyone's opinions and I know that many may dislike my favorite anime shows (but I don't really care, I know everyone has their own tastes in shows so I don't speak loud and throw hate to them). However, many (yes, many, a lot, sooooooo many) say that sports anime shows (especially those with mostly boys) are "not even about sports, but just filled with fanservice". I honestly cannot accept it, the creators of these anime shows put many effort in the concept of sports and every character's motivation or way of playing the sport, not for just fanservice and hot bodies!
-Anime fillers aren't bad things, they can provide a nice and interesting break between major plot arcs. It's only when they're really overdone, the entire arcs are made out of them and it becomes a big issue, and sometimes fillers are mistook as plots themselves, because of too much details and twists. It makes many people confused.
-Many anime shows have side characters or deuteragonists that are waaayyyy more popular than the protagonist/s. Some of them are Shingeki no Kyojin's Levi Ackerman, Bungou Stray Dogs' Osamu Dazai, Boku no Hero Academia's Shoto Todoroki, Naruto's Kakashi Hatake, Re:Zero's Rem, Darling in The Franxx's Zero Two, Mirai Nikki's Yuno Gasai, and many, many more.
-Compared to Yaoi, Yuri is very underrated. I am saying this as a fujoshi; I have to admit, I am much more into Yaoi. But when you look at it, Yuri and Yaoi are quite similar, yes? The only difference is that Yaoi is Boy x Boy and Yuri is Girl x Girl. So then, why is Yuri so not noticed? Until now, I can't think of a solid reason.
-Boku no Hero Academia is a very popular anime, but for some reason, I just can't get into it. Many have already pushed me into watching it, and so I did. But after I've finished S2, I quickly lost interest and motivation into continuing it. I just can't get into it, no matter how many times I try watching it.
-As much as I hate to admit it, many typical female otakus (as I said, I'm not implying to all) only watch anime for their husbands (male crushes). Some mostly watch all-boys anime shows, like Ensemble Stars! or Haikyu!!. I am saying this because I am a female otaku myself, and I'm not going to lie, I have watched many all-boys animes, however, the boys aren't my main reason. I watch anime for the concept and nice plot, not for the characters!
-Even though pirated sites are bad and illegal, majority of the whole Anime fandom watch anime and read manga from these sites. I understand that they simply can't afford Netflix, Funimation, Crunchyroll, or any other legal sites that need money, however, it is more important to support the animators or mangakas through legal sites. Their hard work simply can't just be sold or showcased for free.
-Most of my favorite animes are actually underrated. Honestly, I enjoy watching underrated animes, and they deserve more recognition, too! Like Tanaka-kun wa Itsumo Kedaruge, Gekkan Shoujo Nozaki-kun, Barakamon, and much more.
Anyways, these are all my opinions! I'm sorry if it's too long, I just wanted to share them and let everything out! I was really open while typing these, I guess... I hope some may use a bit of their time to read these. Anyway, thanks!