While acknowledging that we can’t judge books by their covers, how much does the design of a book affect your reading enjoyment? Hardcover vs. softcover? Trade paperback vs. mass market paperback? Font? Illustrations? Etc.?
I can truthfully say that if someone handed me a book with the cover obscured by say, pieces of cardboard taped together, I would be suspicious as to why that was the case, but would likely start to read the book anyway. If it's a good read, it's a good read.
Having said that, if I am looking for a book to read, left to my own devices, I will admit to paying attention to the cover and its condition. Because I have all kinds of arbitrary rules that I impose on my own universe, there are specific things that will make me put a book back rather than take it to read:
1. I do not like movie tie-in book covers. Nope, even when it's something or someone that I like in the illustration. If I want to see the movie, I'll go and see the movie, or rent it. I'm taking the book from the shelf to read the book!
2. I do not enjoy reading books where people have written all over the pages, in the margins, etc., particularly if they have written in ink, and even more so if they have poor handwriting.
3. I will not borrow a book from the library if I look through it, and cannot determine the cause/origin of stains, etc. I do not relish the idea of walking around with someone else's, er, "effluvia" dried onto the pages. (Likewise, if I am sick, or suffering from my allergies, I try not to read a borrowed book.)
4. Even if someone is nice enough to loan me their copy of a book, I won't read it if it's really filthy, shows signs of having been wet, or if I know the person to be a disgusting slob.
I could go on, but won't, both because I'm sure you get my drift by now, and why should I continue digging this black hole of crazy for myself?
I do like old books. I love books with inscriptions in them, especially when they are personal inscriptions from strangers. I am drawn to books with clear lettering on the front and the spine, and that grab me because of cover image or color. I like books that are the only one on a shelf (as in a bookstore), and always at least have to pull them out to see what they are.