 The phrase " have a nice day " is typically spoken by service employees or clerks to customers at the end of a transaction . A mercantile method of expressing " thank you " as in " thank you for shopping with us " or " thank you for using our service " , it is commonly used among people in the United States and by retailers in New Zealand and elsewhere . In the 1970s , the American supermarket chain Kmart opened a store in Brisbane , Australia . The workers were trained to say , " Thank you for shopping at K @-@ Mart . Have a nice day . " 
