I learned several important things as I assembled the Whatever Quilt top (and of course, real quilters know all of this stuff already):
#1. I will never be more than an enthusiastic amateur quilter. Even when I start with my blocks all exactly 8 1/2" square, I still end up with misaligned corners.
#2. Sashings are sort of like painting hallways- you look at them and think, "well, it's narrow, it won't take long to finish", forgetting that it's not the width that matters, but the length. Adding sashings vertically and horizontally doubled the number of seams while only adding 10 1/2" to the width and 15" to the length, which I could have done with a plain border with less fabric, and 4 seams.
#3. It takes all day to assemble 54 blocks with sashings.
#4. Sashings are, however, really pretty, and worth the time, effort, fabric, and thread. Even when my corners don't meet.
#5. The color of the sashing totally affects the perceived color of the quilt itself. Before sashings, the quilt was a jumble of bright colors and patterns. After the sashings, it's still a jumble, but it's a Country Jumble, a much more subdued riot of color and pattern. I like the look, but it's different than I expected.
So, now I get to find out if invisible thread really is.