Believe it or not

Bernice started to notice that something was amiss the third time the escalator started when she had already climbed more than half of the immobile steps. The first two times she had attributed the problem to bad maintenance or slow photocells. Now she glanced over her shoulder and saw the tiny child that had put her featherweight feet gently on the first step and caused the whole thing to start.
It could not be weight; it could not be bad maintenance. It had to be her. Bernice.
She walked slowly to the ticket office to ask for some explanation.  The sliding doors would not open. Yet there were people inside buying or asking for information or simply browsing time tables. She patiently waited outside until a cleaner accidentally triggered the photocell as he walked past with his trolley. Then she queued up with the other travellers.
 
It was not the fact that no-one seemed to take any notice of her or that the sales assistant did not seem to hear her mumbled questions, that finally made her understand. She was used to never making much of an impression. No, the final clue was when Bernice stumbled and fell straight through the ticket counter, bullet proof glass and all.
Bernice had read stories about people who had died and just stepped out of their bodies and continued to live like ghosts without even noticing it. But she had never heard that it could happen to an entire civilization and all its buildings and computers.
It was truly amazing.