First one I've missed in years as we don't finish till Christmas Eve this year. Seen some cracking shiners over the years, some self inflicted.

The Urban dictionary's description of BEF

1. Black Eye Friday
"Black Eye Friday" is a colloquial term used to describe the last Friday before Christmas, due to the severe excess of violence that occurs on that night. This is a direct result of: People drinking more, the army leave, the break up of Universities and Colleges and the miriad of work nights out.
Person one: It's Black Eye Friday tonight!
Person two: Yeah, A&E put extra staff on