if someone says "smile", i just lift my lips and show them my teeth for a second.
i can not smile unless i feel like smiling, and that is never in concert with any other person.
once i was stopped in the street by a religious girl who was doing some "crusade" thing, and she asked to talk to me so i let her.
she asked what makes me "smile", and i said that an electric shock to the back of my neck may make me "smile".
she was on her way after that response, but it was a valid response. an electric shock to the back of my neck would cause contraction in my cheek muscles, so it would be a "smile".
there was nothing else that could make me smile that day.
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i can remember another situation that happened about a year ago.
there was a person who was a "team spirit" person in our office (where i sometimes work) who was new (i did not find out his true role).
he used to come in to my office and ask whether i was "happy". i told him "yes", but he did not seem to believe it.
he tried to instill some kind of "spirit" in me. he was a manager so he was "above" me.
he asked me to "smile" and and i said "no thanks".
him: c'mon Mark. you know that when you smile you feel better.
me: i do not need to feel any other way than i do now thanks.
him: so are you happy with how you feel?
me: i like to be left alone thanks (hint).
him: but you have to integrate with everyone Mark!
me: please!! i want to think about this (a problem i was solving)
him: does it worry you to get close to people?
me: (i started to see his head as rather goofy, and i saw his words as silly, so i smirked about that)
him: ahhhh... got a response from you have i champ?
me: (i was very entertained at his thinking that my smirk was in deference to him. i started to chuckle and i looked at him because i found him entertaining with his stupid persistence in trying (and failing) to make me smile).
i started to laugh then, and he thought at first that he had "brought me out of my shell", but after a little while, he did not like the force of my laugh (it was was severe), and he became defensive, and he left my office soon after.
i do not say "cheese" with my teeth bared.