I took this book---The Birth of Venus by Sarah Dunant, which I can't issue a recommendation or non-recommendation for, since I never got around to reading it---out of the library mostly because when I flipped it open to see if it looked readable or not, I noticed someone had highlighted words in the prologue. (And seemingly only in the prologue, since I flipped through the book and there weren't any more blue blobs jumping out at me.)
My mom impressed on me from a very early age that one does not write in books, especially library books, and I've never been much of a book-annotator. I had a professor my freshman year of college who forced us to make notes and underline things in the anthology of short stories we had for class. It always felt really artificial to me to do this, like I was only making notes because I knew he'd walk around at the beginning of class to make sure everyone had made notes, not because I actually felt I had anything to say about the story that needed to be right there in the margin. Also, it meant I couldn't sell the short story anthology back to the bookstore at the end of semester. I still have it on my shelf, in fact.
So while I don't write in books, myself, there's always something intriguing (to me) about getting a book from the library or a used bookstore that someone has written in. When I was about eleven-ish, I remember getting so excited about a copy of Rudyard Kipling's Just So Stories that had someone's name and address, along with the date they'd presumably acquired the book in the 1930s, written in the front that I absolutely had to own it.
So while highlighting words isn't quite as interesting, I couldn't resist bringing this book home for a closer look. Some of the highlighted words are: cloisters, vocation, surreptitiously, wimple (the prologue is about nuns), and entrails. For some reason the whole process of highlighting polysyllabic words made me think of SATs, but maybe someone not of high school age just wanted to note words they thought they should look up. This is probably a good habit to get into (the looking up, not the highlighting), really, since I have a terrible habit of just assuming I can get the meaning of words from their context and then using them incorrectly for years.
I totally know what "surreptitiously" means, though. Even if spell check has had to fix it for me both times I tried to type it here.