The Importance of City Guards in Fantasy

This is an incredibly important post for writers of epic fantasy and the like!

Legends of Windemere

Legend of Zelda (I think?)

Whenever a city turns up in a fantasy story, these people will be there.  Either as background, battle fodder, or momentary obstacles, the guards are around in some fashion.  We tend to overlook them unless we need some unexpected corpses or government corruption is part of the plot.  Not much personality among these characters either, so what purpose do they serve?...