I generally don't talk about it, but because you asked, I have seen a lot of anime and hate most of it. I have seen Hellsing, Hellsing Ultimate, about 9/10 of the OG run of Fullmetal Alchemist, a lot of Ranma 1/2, Serial Experiments Lain, Akira, some Death Note, La Blue Girl, some tennis one I can't remember the name of, Castlevania, a few Studio Ghibli movies, Attack on Titan S1 & 2, random episodes of Samurai Pizza Cats, all of One Punch Man, Interspecies Reviewers, Slayers, some DiC Sailor Moon, some early Pokemon, and a few Dragonball, YuGiOh, Digimon, and Naruto episodes.

I don't count early GI Joe or Transformers even though they're technically anime, but I didn't like those either.

Of those, I liked Interspecies Reviewers, about 1.5 seasons of OPM, 1 season of Castlevania, and Hellsing Abridged (because it's fucking hilarious).

Here's a random top 10 of reasons:

1. Anime has a horrible habit of having a great premise, a lot of repeated setup, and then zero payoff followed by a new season escalating with the same. In short, great at premise, poor at developing it into a story. And endings? They have no idea how to end a series except for fighting bigger bad guys...
2. And that's IF they can even be arsed to finish a series. I'm aware of the timeframe dynamic between manga and anime. It fucked over Game of Thrones too. Maybe we just agree not to start a show before the source material is done?
3. Much of the animation looks abysmal and the "serious" ones seem to have an awful habit of just... panning over a background or frozen characters in a scene for fucking ever to fill time. I made note of this during Serial Experiments Lain to my friend who was making me watch it and it basically ruined the show for him. It completely wrecked the pacing and was done CONSTANTLY. There were 45 second pans (which I would start audibly counting after 10 seconds) while the main character just monologued "I'm 12 and this is deep" bullshit that was nearly completely disconnected from the plot. There was no reason to do this. Even recent shows like Castlevania did this.
4. Shit just happens that doesn't make any sense in context of the world they've set up. This is endemic from anime I've seen. Anime fans think that randomness is "creative" instead of just "throwing shit at a screen because the writer had a fever dream and it doesn't matter at all if it makes any fucking sense". Spirited Away is basically just this. No, randomness is not creativity, Katy the Penguin of Doom.
5. They're just a different set of tropes than American cartoons, many of which I find to be nonsensical, twee, or cringe-inducing. Bloody nose when you get a boner trope, I'm looking at you.
6. I fucking hate Japanese voice acting (and often for the most part the Americans who dub it, especially in kids shows). This started when Sailor Moon came over and I wanted to kill everyone in the immediate vicinity whenever most of the characters spoke. That shrill panic screaming that was in SM and Pokemon was awful.
7. In the same vein, I also can't stand constant "reaction sounds". Someone saying something mildly surprising that you should have easily realized 10 episodes ago isn't an excuse to stare blankly and make an "AH", "OH", or "UH" noise (sometimes followed by a small choking sound) roughly four hundred times per episode. Humans don't do this.
8. They make movies that just do random shit and don't have anything to do with the show (if not outright contradict the show). Dragonball is especially notorious for this.
9. A really weird number of them throw in Nazis seemingly at random, appropriate time and setting be damned. Need a bad guy? Fucking Nazis!
10. I am constantly inundated with friends that like anime telling me that I should watch whatever their new anime obsession is despite it conforming to 3/4 of bad things on this list because obviously I just haven't watched the right anime.