Why would he stare and act awkward years later?

Today I saw a guy that used to talk to in 2022. We went to one date. Things didn’t go well and we stopped talking. It ended in bad terms. Today I saw him in public after 6 months. I was walking up and he was walking down with his friends. It was dark and I was wearing dark. He immediately recognize me. His friend was talking and he went silent. When I saw him I turned my head down ( I got nervous). Then I looked up so I could steal a glance but he was already staring at me and our eyes met.

Why would he stare and act awkward years later?
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