If you think of the id as the part of yourself that is your baser instincts, the things that bring you pleasure (even and especially if they're unseemly), then the author showing her id is like writing out her kinks over and over, even when they detract from or completely derail the story.

Arguments have been made that the id is the fuel behind a lot of fanfic, and that it's what can make profic squirmy and uncomfortable for many people, though it may satisfy things in other people's ids.

Is that any help?