I hate anything that circles around and wastes my time while trying to kill them. This is especially horrible if you're using short range weapons or a bow. Long range (aoe) weapons tend to excel with these type of enemies.

Fuhlings are just as bad as greydwarves to me. I think they set it up to have them run in circles as a chance to have a "rest" or "prepare" period, but I'm sure it's mostly to annoy us