I live in the United States, so the managers tell the cashier's to smile, talk to the customers, and what to say.
Usually they point to an item and say "I like that as well". I have noticed that all the cashier's at trader Joe's do this, so I suspect they are told to say this.
99% of the time the cashier's don't give a fuck. Sometimes I will talk to a cashier I see regularly and they wouldn't even remember who I was.