AITJ that my brain remember embarrassing moments but forget important things?

Yesterday, I ran into my ex and I told myself, “be cool and act normal. He said “hey” and my brain completely shut down.

I said, “you too.”

He didn’t say anything I could say “you too” to. There was just silence. A pure silence. The kind that lasts forever. I walked away like nothing happened, but I already knew my brain was going to replay that moment over and over again.

What’s crazy I can’t remember deep conversations and anything meaningful from our relationship but this one embarrassing 2 seconds glitch?

My brain forget the conversations but never my own humiliation.