Sweet Pea (the amazon with the speech quirk here) actually frames many of the things she says as if they were book titles -- I've seen it translated as things like "Volume 1: 'What Exactly Might This Be?'" or "The saga of 'A Race Against Time.'" Nobody's quite sure why.
One Piece can definitely get weird sometimes, but it's one of my favorite manga ever. I think the Sabãody Archipelago arc is one of the recent high points -- not stinting on either the wackiness or the darkness that's been shown to underlie it sometimes. Slavery, institutional racism, corrupt, untouchable nobility, a real feeling of how much bigger the world is than just our protagonists...