What's the difference between concentrating and faffing about?

Maybe it's the amount of focus needed. I can faff, or potter, for hours but I can't concentrate on anything.
I've started a new page on the quilting I'm doing.

The two outer cushions started as a bit of tapestry I was making up as I went along, meant to be a rhubarb plant in a terracotta pot for Susan. But I lost impetus and so when quilting came into my head I went to Swarthmore classes and so could use their machine.  The one in Susan's armpit is machine sewn and the other hand.  My hand sewing is pretty appalling, so I'm not sure how well anything that needs washing will hold up. I'm enjoying finding out how to do it though and am even learning how to use a thimble!

  This is from BibliOdyssey