I've said it before...someone at BAA needs to go to Narita and see how it's done there.
They start by apologising for the inconvenience and then request the support of the passenger in the process. Unfailingly polite and helpful, the line teams are concentrated on the task, they don't make inappropriate comments to passengers or each other and they are ready to assist people with bags, coats etc.
It's the one part of the world where I don't feel stressed or upset when arriving or leaving.
The security process can be done properly and professionally.