Soon there will be reality simulators, completely immersive
environments indistinguishable from waking life.  Whether they are
thought of as dreaming or video games is of importance only to
nomenclature.

Someone who is sure they are out of the simulation will notice
artefacts -- indications that reality is itself a simulation.
Architects will put in false awakenings from the very beginning, but
finally the awakening is not false.

The panic that will ensue will serve as a gestalt.  Those who haven't
figured it out won't understand why everyone has gone crazy.  Some of
the touched will seize upon the sign as religion.  Others will fear.
A few won't understand how or if this at all changes the course of
their life.