Well, the problem with such judgments is that if you press someone about her definition of 'literature' or 'literariness,' she will have a hard time finding a criteria that works for everything we have ever called literature. Have you ever felt ashamed or secretive about books you like because they are not on approved reading lists? Have you ever had a teacher, friend, or parent tell you that what you are reading isn't 'literature,' that it may have words printed on a page, but it is somehow inferior in quality to other books? That is, it might be 'literature' in the broad sense of the term (words on a page) but it's not 'literary'?
(A paraphrase, summary, and adaptation of the opening chapter of Terry Eagleton's Introduction to Literary Theory) Or, There Is No Essential, Inherent Category of the 'Literary.'