What makes writing worth reading?

Okay, I'll admit I'm guilty of being one of those "judge a book by its cover" types of people. When I'm at the library and looking for something to read I am waaay more inclined to pick up a book with an interesting cover or with some kind of witty title than the boring novel with the old-fashioned typeface and no cover art, which doesn't look like it's been opened since roughly the time that dinosaurs became extinct. But that one swift action- choosing the glitzy read over a dull looking book- is what we're warned against time and time again. The merit of a piece of writing has nothing to do with it's outward appearance- the "well-dressed" novel might turn out to be so predictable I could cry while the musty-looking story could be a first edition of a beloved classic. What makes writing worth reading is the true literary quality of the piece. A well written book is well structured, flowing and thoughtful; it takes the reader on a journey into the mind of the author. "Good" writing can be descriptive, persuasive. It serves as a transporter into other worlds, other times, and other possibilities. That being said the question also has a highly subjective side to it. What I personally might consider to be the best book ever written might be worth more to one of my friends as a coaster for a coffee table than any form of entertainment or enjoyment. Different people have different tastes in all forms of literature, whether it be a soft spot for romantic comedies, fantasies, or murder mysteries. One person may enjoy the morbid poetry of Poe while another prefers the non-traditional approach taken by E.E. Cummings. At the risk of sounding overly vague and broad writing worth reading is writing that attracts the reader as an individual. It plays to that person's own tastes and preferences. That's one of the main reasons literature is enjoyed by so many different people- it in itself is so diverse and limitless.