If girls "laugh" when they see you but not your attractive sibling?

I have a sibling who gets checked out by girls half the time when we're out & the majority of those girls give flirty looks & smiles when he passes by

NOW with me these same girls or different ones look far ahead if we cross paths

(purposely avoiding eye contact) BUT they sometimes have these exaggerated grins with either a smirk or just straight up laughing as they pass me by or simply form a scowl

Am I being laughed at "low key"

If girls "laugh" when they see you but not your attractive sibling?
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