Passive Aggression

Passive Aggression is the serious form of aggression.  It's also been called 'covert' aggression as opposed to "overt".  It was once called 'female aggression' though it's always been beyond gender.
It's the strike and it's the lock out.  It is the pout compared to the temper tantrum. It's the little boy drawing attention to himself, holding up the class outing, by taking a long time to tie his shoes.
It's the beaurocrats and courts that make themselves look more important by delaying a decision to increase it's cost.  It's the headache feigned by the woman in bed not wanting to have sex but unwilling to be honest with her partner. It's the man who throws up by sticking his fingers down his throat so he can't make the visit to the mother in laws.  It's the strike.
It's the slow down. It's the half measure. It's the half hearted and half brained.  It's devious and deceptive. It's painful and adolescent and causes as much damage in it's permutations as any active or overt aggression.
It's nursed rage. It's revenge. It's the poison as compared to the gun. It's cold smouldering resentment. It's unforgiving.
It's faint praise. It's ugly. It's sick. It's mean. It's common. It's human and animal. I don't know if mollusks and snails do it.
It's immature. It's nasty.  It's pathetic.  It's going slowly to the emergency and arriving just as the patient dies. It's the follow up police moving slowly to the emergency and arriving after the first arriving unliked police gets shot. It's work to rule.  It's "accidentally" forgetting.
I don't think it's 'unconscious' and I don't think the word "passive" is appropriate.  I call aggression either covert or overt.  That puts the onus of proof on the aggressor. I personally hold them guilty until proven innoscent. Mostly I avoid passive aggressive people if  I can.  Life is too short.  Come back when you're toilet trained.