Frustrated

Why does it seem like all book are rated 'R'? Do everyday people really talk like that and I just live in my bubble and don't hear it? I thought only teenagers who are trying to test the limits of their freedoms by being vulgar used such language. I picked up a book called Left Bank by Kate Muir at the library. It sounded cute, and the first couple chapters were, but then it was all about swearing and having affairs. What's the deal?