This made me instantly think of this:
https://xkcd.com/610/

It's kind of a masterpiece. Most of us do live a really boring life in the end, but we're happy in it. We might be thinking big and doing special things when only a few people see us, but the majority might see us as boring people who aren't special and aren't thinking very deep either.

But now to the being the NPC. It's really good if someone doesn't need to take stress about being something. Not everyone needs to be the hero of the world and that's usually enough to be a NPC for most.

It's a very fine line. I would be terrified if I would need to constantly focus on everything. Riding the bicycle home with constant focus on everything. "Ok now push down with left foot.. right foot.. left fooot... right foot... left foot..."

Would that be the ultimate level of not being an NPC?

_{If you know someone who is an NPC, let me go in their house, dig through their stuff, take their money and potions, throw their chickens in the yard and then run away.}