This one is occasionally even acknowledged in-story. For instance, the manga Ayashimon features a protagonist who explicitly has Shounen Protagonist syndrome. And The Eminence in Shadow takes things even further—the protagonist is so infatuated with the secret brooding villain archetype that his play-acting as one eventually becomes real. And of course there’s the whole notion of Chuunibyou.
This one is occasionally even acknowledged in-story. For instance, the manga Ayashimon features a protagonist who explicitly has Shounen Protagonist syndrome. And The Eminence in Shadow takes things even further—the protagonist is so infatuated with the secret brooding villain archetype that his play-acting as one eventually becomes real. And of course there’s the whole notion of Chuunibyou.