Interface and the customer
Adam Greenfield wrote a great article in Losing (inter)face: Customer experience and its discontents. This is a wonderful correlation and has sparked quite a great perspective on interface.
Communication relies on a transfer of information. I have been going through battles with the UPS driver lately and it is all based on that UPS sticky note that is your communication with your driver and the package you hope will arrive. This week a driver left a blank sticky, which UPS customer service stated was not possible, funny because I have it. The driver did not return the following day. The UPS site fails when the driver does not do their part and customer service can not perform properly when the commication fails. Information needs a transaction vehicle, breaking this transaction can lead to a breakdown in trust.