There are NPCs in the game who will ask you to get things for them, usually prompted by the line, "Do you need anything?" However there are a TON of NPCs who actually respond to a different (but similar) trigger that lots of people don't know about.
I don't think any of it's supposed to be a big secret, but people are always surprised when it comes up IC. how about making it so "Need anything?" works on all relevant NPCs?