First of all, the smile from the heart will wrinkle the corners of the eyes, but the smile can't affect the muscles of the corners of the eyes. Even if it does, it is stiff and fleeting.
Secondly, fake smile can be maintained for a very long time, because it lacks the intrinsic motivation of real emotion, so it is difficult to know when it will end. Moreover, there are often inconsistencies between eyes and mouth, facial expressions and body movements.
Thirdly, for most expressions, the sudden beginning and end indicate that people are consciously using the expression.
Finally, when you smile, the expression of the two cheeks is often asymmetric. People who are used to using the right hand pick the left corner of the mouth higher, while people who are used to using the left hand pick the right corner of the mouth higher.
Several ways to recognize fake smile
Don't talk about colleagues' privacy behind their backs - Bu Zai Bei Hou Yi Lun Tong Shi De Yin Si
Avoid the topic by asking the other person questions - Yong Xiang Dui Fang Fa Wen De Fang Shi Bi Kai Hua Ti
Look at the eyes and see the heart - Kan Mu Guang Shi Ren Xin
Principles of inviting guests and asking for help - Qing Ke Qiu Ren Ban Shi Xu Zhang Wo De Yuan Ze
Square inside and square outside - Nei Fang Wai Yuan Yuan Nei You Fang
How to recover the disadvantageous situation after offending the boss - De Zui Shang Si Hou Zen Yang Wan Hui Bu Li Ju Mian
What are the etiquette of toasting - Jing Jiu De Li Yi You Na Xie
Give the full name of the other company - Shuo Chu Dui Fang Gong Si De Quan Ming
Tact, not humble, not haughty - Ji Zhi She Fu Bu Bei Bu Kang