Well, why procrastinate today when you can put it off until tomorrow?
Because chronic procrastinators relish the thrill of riding deadlines to the eleventh hour is why. Confronted with a one week deadline people in general split into two camps:
Those who begin immediately, complete the project in three days, then spend the remaining four days fine-tuning, rewriting, and reflecting on the fruits of their labor. (If the deadline's yanked forward two days, no need to panic.)
In the other camp are those who postpone the inevitable then begin only when the tension becomes unbearable.
And that's the riddle's answer right there: procrastinators are adrenaline junkies.
The endorphin release from solving the problem at 11:59pm is a higher high than completing the project days in advance. (As those with Attention Deficit Disorder well know, it's only adrenaline that allows their minds to focus on any given assignment.)
Such brinkmanship however rarely leads to great work; studies have shown that people are less creative when fighting the clock because time pressure means they can't deeply engage with the problem fully. Creativity requires an incubation period; the subconscious mind needs time to soak in a problem and let ideas bubble up.
And although perfectionism is commonly cited as a cause of procrastination––"it'll never be good enough so I never start"––a 1996 study by Robert Slaney found that adaptive perfectionists are in fact less likely to procrastinate than non-perfectionists.
But take heart, the penalties for skipping a deadline aren't what they were: when the first penitentiary at Folsom was built it had neither walls nor fences, just a white line that if you crossed you got shot.
It was called the deadline.