There are certain NPCs out there we all interact with: they are the trainers, shopkeepers, or bystanders we sometimes incorporate in our RP. I think NPCs shouldn't play huge parts in our RPs but involving them to some extent is a good touch, especially because they are not godmodders, they "know everyone" and many of them can be considered specialists in their fields (magic, booze, crafting, etc.). However, we don't want them to have split personalities and that may happen if we don't pay attention when we include them in our plots.
What I was thinking was a very simple but specific story for those characters like Gregori, Trasok, Harnquist, Jefreca, etc. in which their personality would be detailed. Things like "slow to trust and quick to anger", "kind and always eager to help", "womanizer", "hates warriors", "understands half what he hears and makes up the rest", "picks your pocket should he see the opportunity", and that sort of thing. Now, this would be mainly OOC so it wouldn't fit in their descriptions (after all, unless you are some kind of empath or psychic, you wouldn't know all this with just one look) but it would give us players a sense of what these characters would say or do if we wish to give them a part in our plots.
A thread or sticky with a brief story for these 10+ characters wouldn't take much time to write and would help keeping players from making them do stuff they would never do or godmod on them. I think it would be a simple but useful addition to our settings.
edit: typos >.>