running out of batting, and finding that the fabric shop has sold out but happens to have a funny old bit under the counter which is exactly the right amount, with a little Frankenbatting from the offcuts bin. It's just for this that I keep all the offcuts from quiltmaking. You never know when they will come in handy - quite often because of my incompetence: those skinny strips are fantastically useful if quilt creep has left your batting shy of your top.
It doesn't pay to get smug though, and quilt your work to itself. Doh.