Another try at free motion quilting

I've been trying and trying to do free motion quilting on my tumbling blocks quilt.  After a brief period of success last week I got stuck in a cycle:

Stitch on my quilt.
Flip it over.  Notice loops and tangles.
Rip it out.
Stitch on my quilt.
Flip it over.  Notice loops and tangles.
Rip it out.
Practice on a remnant.  It goes fine.
Stitch on my quilt.
Flip it over.  Notice loops and tangles.
Cry.

The time it went well last week I was stitching on the yellow part of my quilt.  But whenever I stitched on the blue border it went horribly.

Then one day I was ironing a small piece of that blue fabric for another project and I noticed a smell...a plastic, burning smell.

That fabric is polyester.

I have no idea if that affects the ability to do free motion quilting.  Maybe it does - whenever I stitched on the yellow fabric, which is cotton, it was okay.  I decided against ripping off the border, so now I'm just going to do a bunch of straight line stitching to quilt the borders together.  I still want to do free motion quilting in the yellow parts around the blocks.

And speaking of, yesterday I tried FMQ on my treadle for the first time.

It was okay.  No loops, anyway!  The thing on the side is supposed to be a plant, with a stalk and leaves.  I even put my name on it.  Not bad for a first try on the treadle.  The treadle was actually easier than the electric because I was able to go more slowly and have more control over the speed.  I can't wait to practice more and improve.