A portrait! What could be more simple and more complex, more obvious and more profound. (Charles Baudelaire) Human beings are inherently unpredictable, emotional creatures. Therefore, unlike non-human photography, capturing the right expression and look for a portrait heavily leans on how the subject feels at the time. And this is largely determined by how well the photographer can aid the subject in feeling how he/she needs them to in that moment, in order to evoke the right expression and emotion from them for the shot, to create the image that’s needed.