I'm always a little hesitant about self-check out aisles in grocery stores. They look so convenient, but at the same time I'm a little intimidated by the fact I can completely check out an entire grocery cart full of food and not mess up. You can't scan a banana, how am I supposed to pay for this fruit?
Any time I have ever used one of these self checkout machines it has not been a problem in the least. I am never not surprised by how intuitive the machines are. They all seem to have an incredibly simple layout with easy navigation compared to the vast amount of products a grocery store carries. This is a perfect example of a very good service captured in a very specific concise module.
The purpose of all services are to aid the user in one way or another. Many services are electronic machines that replace human labor but many services are still done by people. The example of the self check-out aisle in a grocery store is an example of a very efficient very effective service by a machine that has replaced the need for human labor. I do not doubt that in the near future check out aisles will be completely replaces by this self checkout system.