When you're watching an anime, sometimes it's great to have the characters break the fourth wall and acknowledge that they are, in fact, anime characters. Yes, it can occasionally be jarring, but it's also a moment of connection between viewer and creator, and sometimes – like in Gintama and Osomatsu-san – it's pretty hilarious.
It's also great when anime gets meta and talks about, well, anime. After all, if you weren't interested in anime you wouldn't be watching it. Shirobako takes us inside the anime industry by having its characters work for it, Welcome to the NHK warns of the danger of getting too deep into it, and One Punch Man parodies the shōnen genre to hilarious effect. There's some great meta anime out there, so check out these titles, and vote up the one that most effectively smashes through the fourth wall. shōnen
Gintama is basically the most meta anime in existence. In almost every episode, the characters do something that shows that they know they're in an anime. If they're not questioning the sound effect words, they're complaining about their small budget or warning each other against ruining the show's ratings. There's even an episode where the staff "messes up" and doesn't finish the line work on time, leading the characters to wonder why they can't move properly and why nothing around them is in color.
Viewers might find FLCL (AKA Fooly Cooly) to be a little confusing. Not to worry, though, because the characters don't understand it either, and they're happy to tell you so. Naota asks the audience if they're as confused as he is about the plot, and he can't answer Kamon's question about what the title means – Kamon figured he would know since he's the main character.
Considering the show's refusal to play by typical anime rules, it's no surprise that they're not too keen on preserving the fourth wall, either.
Ōkami-san & Her Seven Companions usually doesn't tread into meta territory, but every once in a while, it does something unique. Not only do the viewers hear the voiceover narrator's comments, but the characters hear them, too. When they don't like what the narrator has to say, they argue or glare – and with a narrator who often makes disparaging comments about their chest sizes, there's a lot to fight about.
One Punch Man is a shōnen parody that is keenly aware of its genre's tropes. While most shōnen heroes end up ridiculously overpowered by the end of their series, Saitama can defeat any enemy with a single punch from the first episode. With no villains who can truly challenge him, he's bored out of his mind.
Despite its disinterested protagonist, One Punch Man is anything but boring. The way the show lovingly skewers shōnen tropes is hilarious – what anime fan hasn't wanted a villain to get decked while he's in the middle of pointlessly explaining his evil plan?