They define proper behavior in various roles. They change fairly often. They initially have no connotation. They are obligatory and are more strongly sanctioned than folkways. Mores tend to change very slowly.
Some examples are bigamy, theft, treason and incest.
They tend to reflect the changing patterns and ideologies in a society. Quite often they are an avenue of expression in modern society. Fashions are those mores that permit a latitude of variation around a major norm. Fashions are widely accepted in a society and are subject to individual expression. Fads are a sub-type of fashions.