There are many ways in which one can draw a smile on one’s face and, at times, infect others with that grimace, which creates an environment full of endless rows of white teeth. As each person is an individual, the way to achieve a smile varies: each one is affected by different reasons, some understandable and some irrational, which lead others to believe that the subject exposing a smile is madly mad or ill with another state of mind condemned by society.
What drives the smile are the emotions that one holds at the moment, so it can be caused by joy, sadness, nerves, etc. On certain occasions where social norms are very latent, one smiles out of commitment. With this idea in mind, before the joke is said by one of the members of a group of friends, some people will laugh and show wide smiles so as not to generate disturbances and to continue being accepted by that social group.
As we see, the causes are diverse and depend on the character of the individuals and how they react to certain incentive around them, for example, it can be good news that generates joy and leads to a smile, or it can be bad news detonating grimace, and in that case, one expresses a certain taste for one’s own or others’ misfortunes.
Whatever the incitement, as a next step we have the technical part: the smile is formed when the muscles of the face contract and the corners of the lips expand to opposite sides. This causes the mouth to be wide enough to allow a view of the dazzling teeth. As a consequence, the lips are embedded in a crescent-shaped grimace horizontally (the curved part of the figure facing down). Given this, many people can become infected and manifest the same reaction, and thus an environment is built with a lot of energy, with a dynamic that attracts other individuals and generates a feeling of welcome.