Annoying the agents is not an official charge, and certainly cannot be the sole charge for a mission, but it is still a serious charge indeed. There are lots of things that can annoy agents: being sent on the mission; the Sue hitting on the agent's lust object; dizziness and falling caused by time rifts and tense switches; getting drenched because the entire fic takes place during a rainstorm; and more. Most of these are either directly or indirectly caused by things that are official charges against the Sue. Annoying the agents is just an added bonus. For one, it makes it a fairly sure thing that the one being charged with this will experience a great deal of pain when they are taken care of.