At the Last Possible Minute

I spent this weekend past trying to write an essay for my film class. I wrote the majority of it Monday morning, the day it was due. This is not for lack of trying, really. Most of you who tried to get a hold of me can attest to the fact that I was bored witless sitting there trying to write this essay all weekend. I eventually did get some kind of quality inspiration on paper, but now I wonder, what triggers that inspiration? Does it just require a time investment, i.e. If I spend 14 hours trying to write the essay I will eventually reach that point of inspiration? Or is it based in closeness to the deadline, i.e. even if I were to have the entire thing written long before hand, I would wind up scrapping it and re-writing becaus of a last minute realization that what I'd written was uninspired crap, that the true inspiration doesn't come until just before the deadline?