I see no hierarchy either. I would frame it slighty different though: We hold it emotionally and experience it mentally.
Ah... you are grappling with the age old question, which came first, the chicken or the egg, the thought or the emotion. I know this puzzle well.
Different schools of thought see it the other way around, such as you find in Cognitive Behavior Therapy. Does the thought precede the emotion, or the emotion precede the thought? I personally see it can arise in either place, or neither, or both simultaneously, etc. It ultimately doesn't matter, since it all happens in a nanosecond anyway.
Regardless of the cause and effect relationships, there is one thing for certain though. They interact with each other in a self-amplifying feedback system. Negative thoughts most definitely increase negative emotions, which in turn feeds back into and increases the negativity of the thoughts, which in turn increase the negativity of the emotions. They feed off of each other.
This is why forgiveness is such a vitally important part in the process of finding mental and emotional health and wellbeing. It breaks that cycle. And moreover, it then replaces the negative feedback loop, with a positive feedback loop. What we hold in our minds, will in fact manifest itself in our emotions and in our physical bodies, through constantly tense muscles, lack of circulation, etc, all of which affects our physical, mental, and emotional health. Positivity increases health. Prolonged negativity, such as carrying around resentments, decreases health.
Repressed negativity has the same effect. While we may have it "out of mind", it is not out of awareness in our bodies, or in our emotions. Our subconscious and unconscious mind are very much part of the whole package deal. Would you agree with this?
How do you measure the effect?
Mental, emotional, spiritual, and physical symptoms. This is why people end up in therapy. And probably the majority of these problems are due to things like this. Negative mental outlooks, for instance, will manifest themselves in someone's posture, which effects blood circulation, which affects mental outlooks, which affects the emotions, which affect the body.
Now, take someone who is slumped over with crappy posture. Have them think of some positive thing, something that energizes them. They now sit up straight, the blood flows better, they feel better, they think more positively, etc. Again, feedback loops, in both negative and positive directions.
How did you reach the conclusion that unforgiveness must lead to repression?
I think you just might be projecting here.
I don't think I said that. It is not a given that it leads to repression. The person has a choice to acknowledge that in themselves and release it. Or that choice may be to rationalize and justify hanging onto it, that it's "needed" for some reason. Now if they do that, eventually unhappiness and disease is going to begin to set in, creating anxiety. That is when people attempt to respond to its presence by pushing it out of mind into the shadows.
Doing that just forestalls and worsens the effect of holding onto it. Now it's no longer obvious why they are so miserable, because they are pushing it away into the closet in order not to face the reason why they need to forgive the other, which is facing the pain that it caused them and letting that go. It's all about holding onto our pain. And then, it's no longer the other who is victimizing us, but ourselves victimizing ourselves.