Ore no Imouto ga Konnani Kawaii Wake ga Nai, Chuunibyou demo Koi ga Shitai! Recommendations
characters who conceal their hobbies and interests by doing "normal" activities such as athletics
Shows in which the main characters have embarrassing (otaku lifestyle) secrets that they are trying to hide from their friends. And of course, they were not successful in hiding their secrets.
Both of them deal with hiding a secret passion of "special" Likes from the rest of Society
Also both have a "Dark Power" Character, if i shall call it like this
Also both are Comedy and Slice of Life Animes
Both main characters have a hobby that they try to hide from other people. Both series are comedy, although Chuunibyou is much better and smarter in humor, and also in the development of characters. The theme and atmosphere are similar in both series is school and otaku style.