I posted this awhile ago but feel it's worth repeating.
The google has abandoned me for the moment. I've been trying to find a story/lesson and can't...I'll have to head to the books. In the meantime, here is the essence.
Let's say you throw a rock up in the air. Then let's say that as that rock is pulled back down to earth by gravity (as it can do nothing else), it hits you on the head. And, when that rocks hit you on the head, you are totally surprised. WHAT!? Where did THAT come from?
To be clear, that is called a self inflicted wound. It would follow that being surprised by that self inflicted wound is called, lack of awareness.
We, ourselves, our mind or mindstuff, citta, is the source of most of our suffering. Owning our actions can go a long way to alleviate that suffering. Put the rock down, see it and acknowledge it. Once you see it you must choose. You can choose to leave it on the ground or you can choose to pick it up and maybe hit yourself on the head again.
It really is entirely up to you.