Watch for crying. Crying is considered to be caused by an explosion of emotion in most culture. Oftentimes crying is considered a sign of sadness or grief, but crying can also be an expression of happiness. Crying can also come about through laughter and humor. Thus , when assessing crying you'll need to look for other signals to determine the appropriate context of the crying.
Crying can also be forced or manipulated in order to gain sympathy or to deceive others. This practice is known as "crocodile tears" , a colloquial expression that draws on the myth that crocodiles 'cry' when catching prey.