"Creating this type of list can help to solidify a sense of group identity, " says Linda Tropp, professor of psychology at the University of Massachusetts Amherst.

BBC: Why do people keep lists of enemies?

Professor Coleman said the use of slang "emerges when people are put in a position where they are bottom of a hierarchy" but have a strong sense of group identity - using it as an "outlet of aggression".

BBC: Slang through the ages

To transmit and display the ritual is to reconfirm a sense of identity within the group and to contribute to the continuity of an important tradition.

UNESCO: Culture