Understanding "Passive aggressive behavior"?

[Edwardo Piet]

I never quite understand exactly what passive aggression is because I find the standard definitions vague and the examples everyone give seem to be very different. It's one thing I've never quite understood the concept of which is kind of weird really because I have grasped much deeper concepts.

Or is it just a very vague thing anyway?

What exactly is it and can we all come to an agreement of some classic examples of the behavior if there are any?

Additionally do you know anyone that is significantly passive aggressive or do you ever feel that you yourself particularly are?

And what is the mildest and severest examples you know of? How bad can it get and how mild can it also be?

I don't understand why understanding it slips past me but for whatever reason(s) it does.

Is it at all linked to self-sabotage or does it mainly affect others?

Is it a common trait or a rare trait? Anytime I google about it I am always dissatisfied in the info and I can never seem to find a general understanding of it that isn't completely disagreed with every other site I read up about it. I don't know - what do others think?

P.S. Is this concept incredibly simple and I just fail to understand because I am socially r-tarded in some way I wonder? lol