If I am upset, I must be mistaken, and I must have chosen wrongly.
"I must have made a wrong decision because I'm not at peace."
If I am feeling anything other than love, joy, happiness, peace, then I've made a wrong decision. And it was me who decided it, meaning that I decided not to be happy by believing something untrue - something that is incorrect.
"I made the decision myself but I can choose otherwise."
If for example I'm feeling loss, I might believe that this loss is legitimate, due to the perceived loss of a valuable person, the loss of a body, the loss of a favorite object or whatever.
But I am a son of God, and there is no loss in sons of God. Therefore what is this loss but a lie? It must be being felt due to a mistaken belief. Somewhere in my mind, if I am feeling loss, I am mistaken, because nothing real can ever be lost.
So my feeling of loss, or unhappiness, or sadness, or grief, or anger, or guilt, or fear, or any other kind of ego emotion that does not exist in God, isn't just "a feeling" sitting there on its own wanting to be felt. It's the RESULT of some decision I made, at some time, to believe something mistakenly, which has resulted in this less-than happy feeling.
So behind the feeling of loss or sadness or anger, there is always something else going on.
"Anger is never justified"
"I am never upset for the reason I think."
If I would be willing to look and find out what it is I believe or have chosen, that is producing a negative feeling, and question the basis of it, it would stop PRODUCING the effect of the negative feeling.
This is somewhat radical because it starts to reveal that any unhappy or unholy feelings you have, you don't necessarily HAVE to have. You don't necessarily have to cry about the loss or whatever, IF you can find out what is CAUSING it and correct the real issue. The issue is always some kind of mistakenness, some wrong belief, some faulty conclusion or valuing, which is resulting in the "effect" of ego emotions being generated. You don't' have to suffer through it.
"It's not God's will that you suffer."
By all means do not deny feelings if all you really can manage is to be swept up in them and feel them. Sometimes you have to have a huge catharsis which is ok. But I also often find myself upset and Jesus is prodding me that I don't really need to be feeling this at all, nor do I have to go through the motions of the release of it through normal human-body means.
If behind every emotion there is a thought or belief or decision, then its my mind that needs to change in order to stop manufacturing this emotional sickness. All negative emotions are what it feels like to believe things which are not true.
It's quite plausible, that you will reach a state where you no longer need to feel any ego emotions ever again. In fact very often now when I go to feel and show a willingness to "just feel it", regardless of its validity, the Holy Spirit steps in and starts to perform a healing on me. He removes it for me when I let him.
"He will undo the consequences of my wrong decision if I will let him."
"I choose to let him by allowing him to choose for God for me."
And so gone are the days of having to just be on an emotional rollercoaster, being thrown around by unhappiness and crying all the time. If you will allow yourself to go deeper and receive healing, to uproot the cause of the feeling, then you can collapse the feeling entirely. It then become no longer necessary to be unhappy or to cry or release or cathart. And ultimately, you will no longer have to cry ever again.
Only the happy feelings that you share with God are real, just as the real thoughts of life and love that you share with him result in and cause those happy feelings. And only the thoughts I think with God are true.