We could spend lots of time trying to find the reason of that anger, but the reality is not that you have anger but that you are anger. Two different things. That is why, external methods can only suppress that feeling of anger for a while, but it will be there until we realize it.

Your last sentence is ambiguous: “What I realize is the more I do yog, this quality is becoming more and more stronger.”
Is that the quality of becoming angry?

Let me share my experience with “yog” or yoga; perhaps this could answer your question.

When I started in this spiritual path, yoga was about feeling love for God. That quality of emitting love made me feel bliss, something which I have not felt before, for there was no opportunity in my life to feel deep by just sitting in meditation.

That new experience was able to “cool me down” for a little while. I felt at peace and at ease. However, some other times, as I understand in your question, negative emotions such as anger could be felt as being really strong.

That sensation may appear to be stronger, but it was just the realization that “I was this calm” individual at one point; which I never had the chance to realize; but then I could see when that calm individual turned around into a monster. Like “Dr. Jekyll and Mr.Hide.”

Thus, Yoga or Yog is a great way to realize our “unchecked negativities,” but it is kind of artificial if I have to sit around every time to “submerge old sanskaras” or my old personality.

This is why quite often you hear people sharing about their old “sanskaras” (predisposition) coming back even after many years of “doing yog.”

However, BapDada has talked about the “fire of yoga.” I have felt that when there is an oppression in my heart due to a past emotion arising. Then, I will feel strongly “giving that to God” or simply feeling until that “thing” dissolves.

I don’t need to label that emotion as “it is this,” but just be aware of that bothersome sensation being with me.

Thus, whatever you think or feel while doing “yog,” should take you to feel deeply. That is the magic of it.

Nevertheless, It is my own appreciation that the practice of the “point” form or the “a-temporal” stage of the self, the soul, that is what brings greater and lasting transformation for me.

This practice has been discussed in avyakt murlis (please read 1969 murlis) and in this blog as well. Please click on the “spiritual efforts” tab for additional articles; or deeply study this article:
http://bkgyan.com/2012/10/25/spiritual-efforts-all-knowledge-is-merged-in-the-awareness-of-the-point/

In that awareness, there is a change of consciousness where the “me” is not there. You don’t have to sit for yog, but it depends on your consciousness and its “location.”

Therefore, changes will be permanent as long as you are in that consciousness. The spiritual work then resides in maintaining yourself motivated to experience that consciousness on a regular basis.

Anger is there because there is an “I” doing things, wanting things, expecting things. If you experience what is to be “out” of the “I,” then there cannot be anger for there is no one to get angry.

The last thing that I would like to share is that we will not get there by “doing things,” but by realizing the self.

Self-realization.