It is normal that when delivering a package to a customer the delivery person will not enter the recipient's house unless invited in. The delivery person's job is simply to deliver the product and have the recipient sign off on it. This simple job can become more complicated when the customer is dissatisfied or rejects the product. In America, great care is taken in maintaining delivery and product accuracy so as to avoid upsetting the customer. Common deliveries include: pizza, flowers, mail, and purified drinking water。