Irrational Exuberance

It’s 4:00 PM and my coworker just did a little jig because his supervisor left slightly early.  My coworker leaves at 5:00 PM normally and his supervisor at 5:30 PM.  But he did a literal dance.  I asked him why, “because it’s Friday and the boss is gone”.  I checked in periodically if he was whittling away at the time left in his day by reading the newspaper, online articles, or even an excessively long coffee break.  Nope, his nose was to the grindstone solidly until 5:00 PM.  On the way out, he did a little shuffle, too.

Did I miss something?