What do you think?

I find incest still tolerable. Youngsters going through puberty might end up feeling attraction towards their family, but what makes me sick is romance between blood related parent and their son/daughter. ugh

your description reminds me of Six Half lol
but
ukes staying in love with abusive seme
that tsundere shit in shoujo anime/manga
for yaoi, continuous sex + sex scenes all look the same is pretty boring too

The weirdest one? Honestly, that rudeness is attractive. I mean come on it'll be like....

Guy: *accidentally bumps into someone* Hi, sorry about that.

Girl: BLEEP you son of a BLEEP BLEEP and your mother's a BLEEP in a bucket of BLEEP BLEEP. I hope you BLEEP and BLEEP and live out the rest of your life in a far off hovel without a friend in the world.

Guy: Oooh, she's fierce and independent. I like it.

The readers. Some of them had to talk shit about some genre that isn't their favourite and then get offended when others bash at them back. Cool, you hated this genre, I understand you're upset so don't read it again. I would appreciate their opinion about disliking it and all but it is unnecessary to offend everyone who liked the genre. Come on, you came to our territory but then talk shit out of nowhere -_-

I'd have to say that something like Monster Musume is kinda weird. A harem anime/manga with ecchi monster girls. Not saying that I'm against it since I do enjoy my cat eared men but it makes me feel some type of way, ya know? :v Even reading this made me feel some type of way. http://www.mangago.me/read-manga/pendulum_kemonohito_omegaverse/ I finished it and it's cute alright but it gives me a sense of wrongness at the same time. XD A guilty pleasure kind of thing I guess.

Oh my gosh, yes! I just finished a manga where the guy was so terrible to the girl. The entire time, I'm just like, "HEIGHTEN YOUR STANDARDS YOU DESERVE BETTER THAN THIS SOB!" XD

When people use backwards logic on me

Example?

WAIT FUCK IM SORRY I THOUGHT IT WAS LIKE WHAT ANNOYED YOU OVERALL

If it would be what annoys me most in manga it would defnitely be when the uke or girl or whatever is so fucking stupid and weak like they can literally do nothing for themselves and get all swoony eyed at the seme. Yeah i love when they love each other but when the seme is just heroic and always trying to help the uke and the uke is a clueless little shit i get mad.

Maybe i just have a thing against super tsun ukes they're so goddamn annoying

For me it depends on type of tsundere (A or B and argumentative or abusive) and the extent. But yeah, helpless characters can get annoying.

I see yeah, tsundere characters can have exceptions but helpless characters are just annoying

I hate ecchi, because girls are always portrait as stupid and like a sexual object. I prefer the type of strong female characters like that teacher from Assassination Classroom and some girls from Naruto. But I dom't read ecchi. In yaoi I hate when the seme is jealous and insecure to the point the uke can't even talk to his friends, especially when he makes the uke feels guilty for this (example: "You were were smiling too much when you were talking to her/him, of course, I get jealous).
I like incest (in ficction), I like the whole forbidden love thing. I never felt attraction to someone related to me, but if I found some friend is, I would support him/her (maybe I wouldn't say "Go on, date this person!", but I would be by his/her side)

Middle schoolers losing their virginity in their second year. It's weird and probably not true about japanese 14 and 15 year olds

And I hate when the uke (or the seme, but it happens most with the uke) takes the whole manga to say he is in love. Damn! I wish there was some manga where one of the characters takes so long to say he is in love that the other find another person (of course, they can be together in the end). But, damn, say how you feel!

When I see a guy is a BL comic crossdressing for whatever stupid reason and some other guy falls head over heels for the "girl." Schmex ensues. "You have a tiny dick but I'm only into girls so you must be a girl. You're hot and like every other yaoi dude I'm only in it for the looks. Dem legs so soft and smooth like a girls mmhm ahh im cumming ahhh oh noes your a guy ew fucc off well ur still hawt im still gonna fuck you becky mhm pantyhoses im into dem also i have a ear fetish and a foot fetish and hand fetish and u have nice hands and feet and ears and ur so kewt you cry when someone steps on a ant im gonna fuk u gud oh well if you insist but first lemme have a shower and clean out my hole and i already can only mastrubte using my hole so im all stretched but still tight even if not u have such big yaoi hands theyd do the job well oh we're at th

When all the main girl or uke does is blush at everything the main guy does like this happens alot in shoujos. For example the main guy does and says some cringy shit like that kabedon or watevs on the mc and the mc just fricken blushes every panel from then on.

More common in anime, always makes me eye roll.

Male MC falls on female MC (or vice versa) and male always ends up in her breasts. Or some obscure event happens causing female character's clothes to be torn resulting in her breast being exposed (or only covered by a string of fabric). Seeing that type of fan service ruins the anime for me.