Ripley Patton has put up a very interesting list about the things that can walay the writer, distracting them from the act of writing while still feeling like 'work' in a writerly sense.
In the comments are a very interesting points, and I wanted to talk a little more about finding balance and setting limits.
I think I'm a very lucky person, in that I am good at setting my own limits, and keeping to them. Not only am I lucky, but I'm also quite rare! However, my ways of determining what I want to do and what my limits are is a constant process in my life. I believe that every second of the day takes choices which can be unconscious, and every day I make firm efforts that all of my choices are the best they can be.
I have a very clear goal in my mind. This means that when something comes up, I can look at it and think "does this decision move me towards my goal?"
If the answer is no, but I'm still interested, I need to ask myself: "What cost does this have?" Every response has a cost. The question is how much of your time/mental energy/stress levels are you willing to assign it? Every minute spent working on something costs something else. If I'm working on editing, I'm not putting out a new story. If I'm writing, then I'm not polishing. It helps me to be aware of the costs of any decision I make.
I'm also rare in that I know that I need to balance my urge to work hard with my urge to play hard - and finding times and places to do exactly that. I need downtime to balance and recharge the uptimes, and this is when Bejeweled comes in handy, or reading books by authors I love. The more I learn about editing and writing, the more I understand why I love some of the authors I do. I sometimes feel like I am relaxing into their arms, safe in the belief that the book I am reading will be well written and well edited, and won't jar me from the story at any point.
The Five Opportunities that Ripleys lists are all things that I have looked at with longing eyes int he past few years. A nice, clearly defined job with a start and end would be something I would love. However that's not the game right now. I just have to keep the loftier goals in mind, and remember what it is I am going to do. Real Life is probably the big Zero that keeps you from writing, as it goes before all others. If you can get Real LIfe into line, then I'm sure you can get the rest of them to fall in line too.