Do you expect more out of books you've bought? By that, I mean, do you hold them to a higher standard because you have a personal (monetary) investment in them?
I've found that I hold purchased books to a higher standard than review requests or library books. And it's really not fair of me, but because I've spent part of my precious book budget on a book, I expect it to be a great one, one I want to read again and again.
So when a book that I've bought is just "okay," I tend to get upset. And so, so disappointed. I then vow to only buy books that have over 4 star ratings on Goodreads and by tried-and-true authors. But, even then, that method fails me. A recent example is Janet Evanovich's Explosive Eighteen. I spent about $14 on the eBook, and it was not worth that at all. It was more like a $2.99 book for me. I vowed never to buy another Evanovich book, and will wait it out on the library waiting list, no matter how many months it may be.
Does this sort of thing happen to you? Do you expect more out of books you've bought?