Amy,
I think when they talk about looking for "our part" in it, that doesn't mean we are invariably at fault in some way. Rather, I think it refers, in those instances where we truly have been wronged by another through no fault of our own, to our own responsibility for how we react to it. Which is what you and lildawg are both talking about, I think.
My time in Al-Anon has taught me a lot about detachment, which is a classic Al-Anon tool (also referenced a great deal by Paul O.), that has to do with refusing to allow the actions of others to take over our emotions. I don't think any of us ever perfects the art of never getting angry. But we can learn to open the hands that are grasping onto it, to keep it from turning into resentment.
It's more than simply not "getting even" with the person who wronged us. It's not allowing that person to live rent-free in our heads. It's freeing ourselves from the suffering of the injury. Sometimes it's adjusting our lives so that we can't be repeatedly victimized by the same person in the same way.