Some people give "birth" to these NPCs. They can't think for them selves and pose no harm but there is strength in their numbers. The simulation would collapse without the NPCs so be grateful for them.
It's easy to spot an NPC. Usually they are doing drone jobs like Truck Driving and Trade Jobs like welding, they love unions because NPCs seek security and they try to make money quickly as possible. NPCs also like certainty. They seek repetitive task and don't have creative expression and are easily told what to do.
NPCs are basically donkeys. They do as they are told to do.

Next time you're at the water cooler at work or eating lunch, try to identify and NPC. Another way to identify an NPC is their sense of style, they lean to what ever stereo type style fits their job. They desperately try to fit in. Remember NPCs don't have creative thought or free thinking. Don't waste your time talking to an NPC, they usually just talk about work and materialistic things. They are put on this planet to serve the economy and nothing more.