I try to use the entire 5 star scale rather than just the top end. The worst book I've ever read deserves my 1 star rating, even if I enjoyed parts of it. I don't need to save that 1 star for "the worst book I can imagine" because that is a book that I'll never read. By the same logic, I'm happy to give books I love 5 stars even if they have noticeable flaws.

My average rating on Goodreads is 3.41 stars.