I know what I enjoy and what my hobbies are, but I feel that I'm not as into things as most others who share my hobbies. For instance, I enjoy reading manga and watching anime, but I feel as though the members of this local anime/manga group I've recently joined, all watch far more anime and read far more manga than I do, and by default, I shouldn't be a member as I'm not familiar with most of the anime and manga they talk about.

Same with people I've talked to online in the past. I've always felt dissociated with them because I feel I'm not as into what they are into, even though we are into the same sorts of things.