Wondering why girls stare sometimes with no facial expression...?

Situation:

This is short and sweet but for about 5 or 6 weeks I've seen this girl staring at me with no facial expression (I see her once a week). As soon as I walk in I catch her looking at me and it will happen three or four times.

Why do girls stare with no facial expression? Heard it before if a girl likes you they usually smile.
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+1 y
I did not expect such a quick response but its doing my head in to be honest with you.
Wondering why girls stare sometimes with no facial expression...?
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