The 11th hour

How often do we put something off only to have to do it in the 11th hour. What innate sense drives us to do something like this to our system. As I sit here contemplating a paper to be written for my Master's courses, I wonder... We are of little perfection seeking to be better at whatever we are going to be, why do we not get stuff out of the way? It might just be a challenge for me at the moment, but still... I wonder.