Imagine you walk out of your house one morning to go to the store to buy some bread. As you walk up the street, every person on the street says hi to you. Sometimes when you reach more crowded intersections, more than one person says hi to you... many try to start up conversations with you. Even stranger, not only do some of them try to start up conversations with you but sometimes several of them will speak entire complete sentences, about completely separate different things, to you at the same time (overlapping their words and turning it all to gibberish"
"How what is are the you weather? doing Pleasant around here enough today for my you friend?" they say, looking at you with hope in their eyes that you will respond. Having no way to really talk to both of these people simultaneously as they have done to you, you kind of shake your head and move on.
As you move toward the store, you start to notice something odd... as you look over your shoulder, you notice that every single person you have passed on your way to the store.... all those people who said "hi" to you and whatnot.... are actually FOLLOWING you. Most of them are doing so silently... but a few of the more creepy ones are actually repeating "Hi!" "Hi!" "Hi!" every 10 feet trying to catch your attention. This would be annoying if it were one person, but it is actually 3 or 4 or 5.
Desperate for a loaf of bread, you continue.
You get to the store, walk to the bread aisle, and start to look through bread. By now you have 50 people following you, who are all piled into the bread aisle with you. They are all acting quite differently. The "hi hi hi" guys are still trying to talk to you... quite distracting when trying to pick bread. A few people trying to look nonchalante are leaning against the muffins polishing their fingernails or sipping on a mug of root beer, watching you out of the corner of their eye. A third group, seemingly desperate for attention and love, is actively giving you advice on which bread you should purchase, once again by talking on top of each other: one is discussing the merits of french bread, another is talking about the new "whole wheat white", and another is actually reciting to you a recipe for bread his grandmother used to cook......
I could go on and on, but hopefully you get the gist of the story. The point? Most NPC's personalities ARE NOT DESIGNED as mean spirited or grumpy. We admins are just often thrown for a loss on how to make an NPC both seem like a real person and yet react positively to this type of situation, which is basically the only type of situation we are ever presented with to roleplay. Hope that clears some things up, and maybe next time as you stalk your favorite NPC, you won't be nearly as quick to assume she is a grumpy pants just because she doesn't appreciate the obsessed entourage of 40 clanking and gabbing armor-clad adventurers.
