How does memory work? I really don't know. It seems logical that you remember the important events in your life: your child's first spoken word, scoring the winning goal, that time I left my car keys in a foreign country. You probably remember these events because you make an effort to do so. Memories will be reinforced by constant re-telling of the events by you or by friends & family. However, even for those important events it is possible for memories to be wrong. Two people can have a shared experience and yet their respective memories of the sequence of events can differ. That can be a heady mix at this time of year, just add the stress brought on by all the preparations and some Christmas spirits and voilà: a barney.