Eyes are powerful communicators as they reflect our emotions. If someone smiles at us but his eyes do not reflect it we consider it a phony smile. When the expressions on our face are also reflected in our eyes they are taken as genuine feelings. Our face is a mirror of our emotions. Though there are cultural differences in the use of various non-verbal cues, facial expression of basic emotions i.e. surprise, fear, anger, disgust, happiness and sadness remains universally same.
Facial expressions are dynamic.
Although it is impossible to indulge in any conversation with blank face, facial expressions are not always a reliable indicator of true emotions. People learn to hide their emotions when they are socially unacceptable or inappropriate. The more skilled the person in doing so the more difficult it becomes to judge his real feelings from his face. However, if you watch carefully micro expressions help in judging true feelings. For example take this situation, you receive a gift which you do not like much.