Lots of books I pick up are doomed before I read one word. Maybe the borders are too big, or the pages are too narrow. Reading books, in addition to being a visual activity, is also a tactile act, holding the weight of it, turning its pages. I finished a book last night that I tore through. I loved the way it was easy to read, not in regards to the phrasing, or the level of skill of the writer, but in the way it was easy to hold and advance through the pages. This next one, the one I started today, however, has some hurdles to jump. Its pages have some mold and water damage, and they are too narrow. The book smells funny. Flipping pages is a chore.
The next time you pick up a book, feel its cover, heft the weight, feel the pages, open it at random, get an idea of how the borders look, how the words are arranged. Does it feel awkward or does it fit in your palms cozily? Go ahead, judge a book by its cover... you won't even have to read one sentence, and you'll know how easily you can absorb the writer's message, and how pleasant it might be for you.
Love your books; they come in all shapes and sizes.