The one thing I am pretty sick of in manga/anime, particularely in shonen manga, is how everyone has to explain every single thing that happens.
They can't just leave things for the viewer to figure out, or simply use visual language or whatever.
One example would be the latest chapter of the Rock Lee spin-off of Naruto.
This page here:
http://mangastream.com/read/rock_lee/43080294/25
I just want to murder the bloody turtle, or simply yell at it "Yeah, I've got eyes, I can see that. Just shut up."
One Piece itself is quite guilty of this as well.
I only noticed it recently, but a big percentage of OP's "humour" is someone doing something, and someone else explaining the joke with a yell and an angry face.
Now I only used examples of humour in mangas to illustrate my point, but the idea of how things are overexplained can be generalized to everything else.
Shonen mangakas have absolutely no idea what "show don't tell" even means.
Or maybe they're so scared that people won't get what they're getting at, they just have to explain it.
That's pretty insulting to the audience in a way, when you think about it.
However, the biggest criminal in this departement is hunter x hunter. And this is one reason why I can't stand that manga.
But everyone seems to love it here so I'll just say nothing. Don't wanna end up sounding like an ass.