Original: Participants are often placed in exotic locations or abnormal situations, and are sometimes coached, to act in certain scripted ways by off-screen "story editors" or "segment producers," with the portrayal of events and speech manipulated and contrived to create an illusion of reality through editing and other post-production techniques.
Simplified: Many shows portray a modified and highly influenced form of reality, with participants put in exotic locations or abnormal situations, sometimes told to act certain ways, and with events on screen sometimes changed by editing.