There are three reasons this is stupid.
- It's total property damage. This book is not yours. It does not belong to you. If you borrowed a book from a friend, you would want to return it in an equally good condition as when you took it, right? So what's different about a library? You just don't write in books that aren't yours.
- What is the point for you? So, you're reading a book and you've come across a passage you really like. You mark it with a Post-It or underline it or something so you can come back to it later. So this is my question: When it's not your book, what does this do for you? It's going back to the library, so you can't come back to it. Do you just compulsively underline things no matter what type of book?
- I don't wanna see it. I'm reading this book right now that has stuff underlined and it's bothering me so much! It's like they're telling me what I'm supposed to find profound/well-written. I'd like to read my book without your input, thanks.