Christmas is a time for giving and being merry - but it's also a time when your colleagues can morph into monsters.
The annual arrival of tinsel, mistletoe and jingle bells can transform a normally rational and well-mannered employee into another person entirely, warns a recruitment company.
Global recruitment company Robert Half has compiled a list of Christmas characters to make sure those who pick up unattractive traits during the silly season don't cross the line from festive to frustrating.
The Not-So-Secret Shopper - prone to spending excessive time shopping - is warned to reign in the spending and make sure it's done only outside of work hours.
While those who take the festive costumes too far - the Human Holiday Display - are advised to keep it in moderation.