We had first date yesterday. He was waiting me outside the restaurant. When he saw me he looked at me and then quickly looked back at me?

I walked towards him and said hi to him and he said hi back. Then he turned to walk towards the entrance of the restaurant but seconds after doing that he looked back at me with slight smile.
We had first date yesterday. He was waiting me outside the restaurant. When he saw me he looked at me and then quickly looked back at me?
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