Main character better then anybody
It occurs in shounen anime. It's when the main characters, with less experience and skills, can kill / defeat an enemy who is mega-powerful without a problem (or there was a problem but somehow they defeated it). My point is that the person who is very high-skilled COULD NOT defeat it and then our main character steps-in and everything is sorted out.
Example: In Naruto (and Shippuuden), Naruto most of the time ONLY uses Rasengan or clone jutsu and CAN defeat anybody, well, sometimes along with his friends. If you see in this anime an qualified ninja can be killed with ONE hit whereas for our main characters who are still just learning it can take little effort to defeat.
Another example is Soul eater (watch ending/major spoiler ahead) - Shinigami-sama couldn't defeat Asura whereas Maka defeated him with some wisdom words and defeated him using bravery........really? -.-
Character that look like a child yet actually is older
I see a cute little girl..... so kawaii <3............but then realise that this little girl who looks like 7yrs old is a ten years older than you think or so??? It happened multiple of times when I just though that the character is a child but actually is like 15-18yrs. Japan sometimes do weird stuff.
Example: In Corpse Party, the girl called Yuka looks like she's about 7-8 years, but in actual fact she's 14yrs!!! I haven't onlu judged her in appearance but also her personality. I'm not into these bizarre anime which concentrates in this kind of stuff so not many examples.
Author forgets about the story line
*Sarcastic Tone* Why concentrate on the main story? Why, while you can put dozen of fillers or
For example, in Naruto Shippuuden there's something important to the story line going on and then BANG, the last episode was very exciting? Well before continuing the story we will give you some flashbacks, not one, but dozen!!*applause*. The latest anime that I've watched - Brynhildr in the Darkness - the mystery is awesome as well as the plot yet it seems cause of many unneeded fanservice every information was pushed towards the end :(Many anime losed great potential in these ways.
Ending with a cliffhanger
It isn't like I want to see what happens next....nah. The author either finishes the anime too early or adds another mystery or information which make anime seem unfinished and left out. You may love the show but when you NEED more, you won't get anyhow which lowers your opinion. I don't mind if they actually continue someday but it's terrible to know that it won't ever continue!
For Example, Shaman king - I love it but ending with; "Another Shaman Fight is coming [END]" So who the hell becomes the King? At least they could do a remake based on the manga. Angel Beats had also an awful end; like what was that ??? [
Creating Great SIDE Character
Not only main characters may be amazing and wonderful, you know? It occurs when a side character ONLY appears in 2? 3? episodes, and then never appear again. As a fan of this character I feel like heart-broken - why do you not give them a bigger role? It also can come in pairs where the main couple appears on the screen all the time, whereas there is just a wee couple on the side which processes once in the millions of times in the one serie!!
For Example; in Hirunaka no Ryuusei (sorry as it's a manga) there's Suzume related couples and there's Nekota x Togyu which was saw togather like 5 chapters out of +65. Another example are Izaya's sisters from Drrr! - such a good character idea and I see a great story and humour yet they only appear I think one episode D:
So it's not like I'm a hater or anything but I love so many anime, yet I personally feel like they could be better. Some of the reasons make my opinion lower and get dissapointed as of how they ruined such a great idea and show. After writting this post I realised how I'm negative towards Naruto O_O Gomenasai!!! It's just it frustrated me too much.... Finally, I honestly love watching but do you find something annoying which occurs multiple of times in one serie or in various of series.
Post Question: What do you find annoying about manga or anime?