Psycho NPCs
Never really had a GM with pointless NPCs...when there were psycho NPCs, they were a plot device. Didn't feel that way all the time, but as the game went on longer, the real reason for those kinds of NPCs became apparent.
So, I guess my take on it is, unless you're the GM, you can't really know that an NPC is just some psycho element to add chaos and suffering in the game, or if that kind of behavior is going to become a plot element as the game moves forward (maybe you tangle with the wizard who made the NPC a raving psychotic, for instance...)
If it bugs you that much, address it with the GM...or find another game...