A Beatles, song, movie, and album (actually a soundtrack for the film) All three of them are absolute classics. The phrase 'a hard day's night' was actually created accidentaly by Ringo Starr, who often combined two phrases to create a new one.

The essence and summary of having lived the 'day' of ones life in 'darkness'. It has been... denotes a looking back or hindsight and the choise of the word 'hard' implies difficulty. Generally such epiphany comes sadly late.

Last minute, enlightenment is frequently found where mill stones were considdered mile stones.