Guilt, like offense, is self-imposed. It is not enforced from outside. It solely comes from inside. Grasp that and own it, and the world is a much better place.
An analogy might help... if I am riding my motorcycle down the road, and a car turns in front of me and I hit them and crash, I can react two different ways: Blame: "That motherfucker turned right in front of me! He broke my arm and destroyed my bike!" Own It: "Goddamn. I've been in an accident, my arm is broken, and my beautiful bike is destroyed. Was I going too fast? Was my headlight working? Should I have been in the other lane? How could I have avoided this?" In the first example, there is no resolution. I am completely disempowered to do anything to make my situation better. It will sit in the back of my mind forever and will always be "that asshole that hit me." I have given all the power in the situation to the other person (who is clearly a dick because he ran over me and my motorcycle), and that thorn is now stuck in my brain for ever. In the second example, I have agency. I am empowered. I can - and will! - answer every single one of those questions. I will learn from the situation. I will become a better rider because I have analyzed the situation and my actions deeply. And it will live on in my mind as "that motorcycle accident I had", rather than letting that other person live in my brain for ever. So. To answer your question: A world in which you have agency, or power over your situation, is a world that you are the master of. You hold the steering wheel. You are the driving force. The alternative is to be someone that the world acts on. The world is inexplicable and unpredictable and spiteful and you need to defend yourself against the vagaries that are constantly visited upon you. Is it just playing word games with yourself in your head? Yes. Essentially. But it works.
Thanks for the elaboration. I see what you mean, and on my better days I do my best to follow through what I came to call "controlling what you can". Clearly, you can't control the outside world - and we're often dillusional enough to think that we can, thanks to our overblown ego (children are the perfect examples of that) - so do what's in your power to control what you can, which is... you. Your reactions, your perception of things and of yourself... It's a good way of thinking - just difficult to follow for me at times.
When you own your actions you decide how you feel about them. Own your actions, realize guilt won't get you any farther and will only drag you down, learn from mistakes, apologize to those who deserve it, and move forward guilt free. It's like realizing being angry at traffic won't make things move any faster, it will just ruin your day. Feeling guilty won't change what happened, it will just keep you from growing. The situation remains but the useless negative emotional state is replaced with something positive.
Koans are profound riddles to test someone's understandings of Buddhist concepts. They have orthodox answers that can be hard to understand because they can be very complex and pretty much require a cultural background in Buddhist philosophy and history, which obviously many people don't. The Western world interpretation of Koans is a bit more superficial. They're seen as something that's there to help you expand yourself, by finding your own answer with your personal understandings and worldview. You can often come to a deep self discovery through seemingly very simple statements. Because your answer is yours and it has been brought about by personal discovery, it can often feel very profound.