I noticed the same thing in college. For me the issue is getting started. Sometimes, I have a mentality of "I don't have time to do this justice so I'll put it off," not wanting to start working imperfectly. A couple of drinks and getting started is a breeze. Then, inertia can carry me from there.
It makes me less worried about what my initial quality/starting point and less overwhelmed about the scope or how much is left to do. Also, I get less distracted by external going on's in my life. I remember reading something about it slowing down your multitasking (background processes thinking about other things) so you focus at the task at hand. Wonder if I can find that article again.