"There is nothing either good or bad, but thinking makes it so." William Shakespeare
We naturally think of those who frustrate us as "bad", and those who give to us as "good". It is the most basic way of categorizing our experiences. I believe some of that is okay, especially when we do this briefly in the moment. However, I think we get ourselves in trouble when we make the people we're frustrated by into "bad" people in our minds; that is, making them into fairly permanently "bad" people. The problem is that we create and hold onto resentments when we do this, not letting people off the hook. There are certain people in my life that are easy for me to think of as "bad", and I have to keep an eye on this.
I believe what we resent in others, we resent in ourselves. And what we forgive in others, we forgive in ourselves. This always works both ways. So forgiveness, letting people off the hook, really is a kindness to ourselves. If you want to feel forgiven, if you want to let go of guilt, then take a look at what's literally holding you back.
So you might take a look in the mirror and see what resentments you're holding onto, what people you think of as "bad", and what this might be costing you in peace of mind.