When I read books, I usually mentally assign letter grades to them. These grades range from F- (I am embarrassed for the author that this is available for other people to read, and/or I'm furious that the author/publisher charged money for this) to A+ (I forgot to write notes because all the fabulousness made it impossible to stop reading).
When I cross-post on sites like BookLikes or LibraryThing, I then convert my letter grades into star ratings. I'm thrilled that both these sites allow half-stars, but even that isn't always good enough. For example, I mentally give a book a B+, but then I balk at giving it 4.5 stars, because it feels too much like giving it an A- and the book wasn't quite that good. My inner perfectionist has a meltdown, I give the book 4 stars, and then I feel guilty because it wasn't really a 4-star book either.
In 2014, I want to be better about saying “These are how my star ratings work, and if someone mistakes 4.5 stars for an A- when it was actually a B+ book, that's not my problem! I'm going to assign this star rating and then not think about it anymore!”
So there. And, yes, I know I tend to overthink things. I can't help it.