The day after is a way of saying something epic or terrible happened the nite before,in reference to the droping of an A-Bomb and it's undeniable impact on ones life. Here are some nites that could lead to a day after
1.Hardcore drinking nite.
2.Ending up in jail for any numerous reasons.
3.Epic sexual conquest.
4.Being on the wrong end of a beatdown.
5.Not remembering last nite at all.
dude 1: I have a killer hangover and don't rember anything about last nite.
dude 2:Ahh, The day after...