Today's fresh Upsideclown is brought to us by James.
As a starting point, we take the basic philosophical tenet that all the conscious actions of an individual are caused by some personal mental impulse to perform that particular action over any another alternative action. For the purpose of simplicity, we shall state that the way an individual chooses between alternative actions is by assessing the utility produced by each action. Where one action is determined to produce more utility than any of the alternatives, then that action is the one pursued.
For your information, education, and to tell you exactly why (with diagrams) you arse around so much when there're things to do: An Essay in Procrastination.