Have you ever encountered your high school bully after 5 years? Had anger sensation?

While I was waiting to get a document on a government service place, I saw and encountered my high school bully after 5 years. He was using a iphone, was talking on the phone happy, was still fit, had expensive clothes and stuff he didn't have in high school. He didn't saw me, but I noticed him. It looks like he too needs money and financial help services. While I was still using cheap clothes and stuff. Thank luck I was with my sister. I experienced a feeling of anger that I wanted to pick a fight with him, because this time I was more mature and had strength to punch him and knock him out. Of course I didn't do that but still, I had the idea. I still after 20 minutes ago, I have this anger in me that is making me feel uncomfortable. Like if I traveled back in time, to a time I was very depressed. Those horrible memories came back. Have you ever experienced this before? How did you deal with it? To let go of the anger. I want to get rid of this anxiety.

Yes but i gave him a massive ***** slap! That showed him!