The final day of a FEX, when all of your garrison dreams come true. Spirits are high, and everyone is merry with thoughts of hot showers and clean beds that night. Magical FEXmas miracles occur on this day, to include surprise buses that pick you up halfway through a conditioning hike so you don't have to drag a full sustainment load and M240B medium machine gun another 6 freakin miles.

Literally everyone, ever. Including the writer of this definition.