I add.

Many buyers are confident that if the seller works here, he should know everything about the product, it is his duty, he receives money for it.

- many patients are confident that if a doctor works here, he should know about diseases everything, this is his duty, he gets money for it.

Many parents believe that if a teacher works here, he should know everything about the curriculum, this is his duty.

- Many customers are confident that if the sanitary technician works here, he should...

You are right. In fact, it is enough to just sit comfortably on a chair for a salary.