Mary Jane made an excellent point when she told me "You can't think about what NOT to do. Your brain just won't grasp it." I understand this from what I learned about dealing with my children. Barbara Coloroso gives the example of telling children "Don't touch" in a china shop. When you say that, you put the idea of touching into their minds. Instead, she says to tell them "Put your hands in your pockets or behind your backs." In this case the little hands have a choice to make that has nothing to do with the breakables and therefore keeps them safe.
So I need to find something else to say to myself besides "Don't buy more yarn." I've decided that it should be "Knit more sweaters." But I don't think that's going to be enough because my brain automatically finishes the statement to be "You can't buy more yarn until you knit up all the sweaters." It could take me years to knit through what I currently have and we're back to the can't.
I used to have a yarn budget, in which I gave myself a certain amount of money each paycheck. But when Jim lost his work, I felt I had to stop that. Since he's picked up some work this summer, I guess I felt the pressure was off and hence we had yarn purchases. So, to keep the output of FOs greater than the input of new yarn, I've decided to reward myself with a certain amount of yarn money for each finished sweater. I figure I'll have to knit two or three sweaters to "earn" enough to buy new yarn.
I don't know if it's going to work, but I'm going to try. One thing I've learned, everybody does things differently. You've got to keep trying till you find out what works for you.
Somehow this is all tied in with losing my car. Take a look at this picture. This is never going to drive again.

But man, reality bites.