How about I break the spines of my friend's book when he annoys me!
Why would you damage a friend's book that way?
I think it makes me cool. Everyone hates a bookworm, right?
Damaging your friend's books is really rude. Everyone gets annoyed sometimes, but destroying other people's stuff is a good way to lose all your friends.
My friends like me a lot. They would probably understand and care less about a few broken books.
This is not just about books, it's about respecting other people and their belongings. It does not make you look cool to destroy someone's book. It makes you look rude, like a jerk.