What makes writing worth reading?

I do not think that their is one answer to this question. I believe that every person has a different answer for this question. A book, or any other type of writing, must first be well written to be worth reading. The subject must also be something interesting to a person. This is where personal taste comes in, the definition of interesting can vary from person to person. The content must also be on the readers level. If a fifth grader were to pick up a book that is targeted to students in first grade, they will not think that it is worth reading.
The content of the writing must also have some sort of information for the reader, no matter how basic it may be. This again brings in the level of the reader. For a first grader the information will be very basic, but an older student should be able to get a good amount of knowledge out of the writing.