I will answer this with an example of my experience.
I was driving my car. Another car was there in front of me going very slowly. I sounded the horn (as it is a practice) to let me go, as I was in a hurry. There was no response, I sounded again and again and became impatient. The other driver went to a side a little as if he was giving the way and when I moved forward he came to the right and I had to stop the car. My car touched his car a little, no scratch nothing. We both got down and he started shouting at me in filthy language. I told him that he was at fault, but he did not care and continued to use the filthy language. I am not used to such language so I was upset and left. I was in a hurry. This incident was lingering in my mind all day.
Next day I sat in the pooja room, still with the incident in my mind and thinking that why God has punished me like this and so on. Then suddenly I started analysing the matter.
Whose is at fault me or him. Instead of sounding the horn, had I waited a little more time and as soon as there is way I should have moved. Why should I keep on sounding the horn. Why so impatience? That means my ego is overpowering me. So, I am at fault. So for my ego and impatience I was punished. Had I shown some patience and waited, I would not have been in such an embarrassing situation of my life. May God wanted me to know this. When I realised this I felt comfortable in my heart. Since then I was cautious and trying to be patient with people, while driving or talking or doing anything.
Knowing about my ego and impatience, I think is self-knowledge. It is not disastrous. It shows the correct path. You need not know about it seperately. It comes in to your mind automatically.
This is my feeling.