Too many topics, too little time

I can see for smiles and smiles. Spot the fake smiles. Can you tell the difference between a fake smile and a real smile? [MetaFilter]

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i like to smile, not the huge gaping mouth teeth baring kind, but the little upturn at the ends of my mouth kind. i smile for all kinds of reasons, usually i make myself smile, now i'm not sure if that is a 'fake smile' or not, but it works for me.