Returning Lost Objects (Hashavat Aveida)

You are required to return a lost object (hashavat aveida) to its Jewish owner if you can. This is a Torah commandment.
Note It is saintly behavior to return lost objects to non-Jews, too, if it will be a kiddush Hashem.
Note You should tell a person if his or her cigarettes fall out of a pocket, even though the cigarettes are dangerous to the smoker's health.