When you come to a stop?

Yesterday, I got three quilts prepped and stitched on the zippers ready to be loaded on the machine. I'm finally getting Susan's quilt on the machine. She gave it to me in Sept/Oct and said it wasn't needed until after the first of the year. So of course, it got delayed until then. Well, now it's on the machine and the beautiful fabric that she picked for the borders doesn't work with any of the thread I have here in the studio. So... I had to order some more thread! And so now, I'm stalled until the thread arrives. What should I do? I thought about unzipping it and putting another quilt on, but that quilt probably won't be finished by the time that the thread gets here and I'll feel like I need to get Susan's quilt back on. So I decided that I get to work/piece on the Happy Ric Rac quilt that I've been working on.

What do you do when you get stopped in your tracks working on a project????