When Jonas read a headline saying a well-known product was dangerous, he shared the article with his friends. A friend asked who had written it and which sources it relied on. Jonas then discovered that the article was several years old. It also concerned a different version of the product from the one currently sold. He deleted the post and explained why. The incident made him reflect on his use of social media. He began reading complete articles before sharing them and checking whether other newsrooms described the issue in the same way. He also learned to distinguish news, commentary and advertising. Even when a text looks professional, its claims may not be well documented. Jonas therefore thinks source criticism is not about doubting everything. It is about asking relevant questions and being willing to change your mind when you receive new information.