'X' became symbolic for a kiss because in the middle ages when alot of people were illiterate and they used to sign documents with an X and then kiss it for sincerity.
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Kissing actually has the biological purpose of passing on biological information and chemical signals to assess mating possibilities and status.
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According to the New York Times, a study conducted during the 1980's found that men who kiss their wives before leaving for work live longer, get into fewer car accidents, and have a higher income than married men who don't.
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Men who kiss their wives in the morning live five years longer than those who don't.
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When you kiss someone for the first time, you get a spike in the neurotransmitter dopamine, making you crave more.
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On average, a human being will have sex more than 3,000 times and spend two weeks kissing in their lifetime.
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As a rule, 66 percent of people keep their eyes closed while kissing. The rest take pleasure in watching the emotions run the gamut on the faces of their partners.
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Research has shown that allowing chocolate to melt in your mouth produced brain and heart rate activity that was simliar to - and even stronger than - that produced with passionate kissing.
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