Ahem... [Prof. Wobbly puts her mitre on]: the PA dynamic.
Passive aggressive behaviour happens when a child has been taught in FOO that the expression of anger is absolutely pathological, vicious and dangerous.
They then filter all their experiences though that distortion (why do all bad things happen to me/don't express anger it is dangerous/once I start I can't stop), and project their hidden anger on to their victim. THEY KNOW EXACTLY WHAT THEY ARE DOING. This is the drip, drip, drip of Chinese Water torture (countless little PA acts) until the person unconsciously holding the anger gets one drop/act too many and explodes in rage and a temper tantrum.
The PA person has then achieved his goal: 1. he has had his hidden anger expressed. 2. he is in control. 3. he is in the victim mode with the other person as the unreasonable aggressor ('I said I was going to do it after my bath. I didn't know you wanted it done now, whats your problem?). and unfortunately 4. he has had his belief that the viciousness of anger confirmed, and 'thankfuly I can stay calm and not lose control like that crazy person' so his PA beliefs are confirmed.
The targetted victim is shaken by the extent of their rage and loss of control over such a little thing (because they are completely unaware of the PA dynamic that has been happening for days/months), feels ashamed, apologises profusely and tries to become a better human being - until the next time.
Passive aggressive acts follow a continuum, from mild (agreeing to do something - and then not doing it, being late, being slow) to pathological. They want to hurt the other person so bad they hurt themselves to (eating disorders, affairs).
How to stop the PA cycle: recognise the hidden anger and self-talk/self-soothe to not to take it on board. Benignly confront the PA person 'you seem a little angry in your being asked to take the rubbish out and maybe we can talk about this when you are ready', then set consequences 'the truck is in the next street, so if you want a bath now, then you will have to take the rubbish to recycling later'.
You have to work really hard at not rewarding the PA behaviour which is getting angry or doing the job yourself.
In all of this I get an F -.