I'll broadly define Scripts as recurring conversations in everyday life. They are situational and range from the banality of "How about the weather?" to something more loaded like "Tell me why I should hire you." Almost every conversation has an associated script and expectations on both sides of the conversation. If you know the function of a script you can better anticipate the needs of the person(s) you're speaking with.
As an example, The 5 Whys, are an effective script for helping a client articulate their goals.
Personally, I love conversations that veer from known scripts into unexpected territory because participants need to switch off their autopilot and pay attention. Ironically, the people who know me can anticipate that I will go off-script so even my desire to break the script becomes a script!