I find myself procrastinating the most when I know what what I'm doing will likely be interrupted, even if it's hours down the line. For instance, even if I can work on a certain thing for 3 hours, when I get word that I'm probably going to have to work on something else for the rest of the day, chances are I'll take those 3 hours less seriously because I know that, when I come back to the task the following day, I'll have to mentally start over. Even if I consciously try to push through it, the back of my mind keeps shouting "What's the point?"