Our inner state of emotions are easily guessed through are facial expressions. So when someone smiles that shows that he is calm, not angry and have friendly attitude towards the other person and many more things can be depicted just by smiling at someone with different types of smiles.
There are many reasons why we smile like while taking pics we usually give a pleasant smile because we want to capture that moment as a happy moment of life. We also smile when we are tickled by somebody. This is because we are touched at the weak points of our body which in turn releases some hormones that creates the feeling of pleasure in our mind and hence causes breathlessness and smile. Tickling happens only if the person is touched gently but if the touch is with force and harsh then the particular person can go into unconscious state.
Smile is deep within our primate nature. It depicts positive social relationships by passing a smile to an individual gives him the signal that â€œdonâ€™t be afraid of me I will not harm you and we can have friendly interactionsâ€. Smile given by a woman to a man shows her attraction towards him but it is also necessary for the man to understand the meaning of her smiles.
Other than happiness a person also smiles when he is feeling nervous just to hide his nervousness. He sometimes smiles when feeling sad because he does not want to drop a tear and also when feeling angry and not want to hurt the other person. So we can say that smile is a good way for the self control.
Smile depicts different meanings according to the situation, past experience, mood, body language etc.