I thought the sneezing was a lot of fun to watch, and probably a mix up of animations. But I examined the cal3d file and used /testanim to see the animations, and the sneezing/headbanging is definately the idle_var animation that will play every 20 secs (hardcoded). So I guess this is what it is supposed to look like. Greeting is different (it looks like they think you are mad). Casting looks beautiful but we never see that animation in game.
Idle variations start after a random time interval, which you can increase as THomPhoenix described. You could also change the animation for one of the others (such as casting). This will only show on your client.