Urgency Forces Concentration
It's the simple physics of Parkinson's law, work expands to fill the time allocated. On the days where I have limited free time, my mind is forced to concentrate and focus on the task at hand. But on the days where I have seemingly unlimited free time, like today, my mind tends to wander off and do other stuff.
When time is scarce, we have no choice but to act. But when time is plentiful, what's stopping us from wasting an hour here and there? We'll still have plenty of time to act, until we don't. In which case, time becomes scarce and we have no choice but to act. Isn't this how a typical procrastinator behaves? Isn't this how we all behave?