It was Tom Peters who remarked that these days common courtesy is a strategic differentiator.
Most customers just want the basics: A polite person, who treats them as a human being, listens to what they need and then acts to deliver it. Good service is not rocket-science.
Small things impress: being greeted by name, someone knowing what you prefer – and these things are easy in services where such information can be captured, like staying in a hotel or flying.
So often service comes down to doing the basics well. But think of all the things that can get in the way: scripts, procedures, IT systems, time limits, IVRs and so on. People who manage to do a good job on the basics are often doing so in spite of their system.