Why is "idle speech" one of the ten unwholesome actions?
So how should I interpret the Buddha's teachings on idle speech for lay followers? 

Opening pleasantries are not idle talk; they frame a discussion by providing social context:


  He went by carriage as far as the terrain allowed, then descended and approached the Buddha on foot, and exchanged greetings with him. --DN16


And neither is talking about suffering, its origin, its escape and the path to escape.


  “Mendicants, do you remember the four noble truths that I taught?"


Have you noticed that although people may idly brag about their wealth, good family and good fortune, what they often really wish to talk about is their...suffering? Indeed, there seems to be a high correlation between idle talk and suffering.

Therefore, from a practical point of view, I've found that we can all talk about our own suffering and its escape. Such talk is not idle and often leads to friendships and trust. 

In terms of movies and shows as idle talk, even these are opportunities to discuss suffering. Movies and shows are all about suffering. 

So when someone approaches with idle talk, gently listen and ask them about their suffering. Then listen and speak with an open heart. Become a quiet person known as a good listener and a good friend.


  Good friends, companions, and associates are the whole of the spiritual life. --SN3.18