Context: You're in a super really happy mood and you have a big grin on your face when you just happen to see someone you know (not a stranger). They look surprised, don't smile back and say your face is creepy.
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(For my case it was my mum who said that. Usually would say to smile more to me and when I was told that comment I was a bit stunned while confused, still was happy, and simply moved on. Though that was a bit of an awkward disaster to me and that little best happiness I could have in a day 'feeling all positive' was gone.)