Their extreme texture and fuzziness made it almost impossible to see where to put the hook for the next stitch.
Then someone let me in on the secret to making novelty yarns behave: Just add a plain yarn to crochet along with the ornery fancy yarn.
Simple, but effective. You can actually see the stitches. And the plain yarn adds body and helps the item keep its shape.
NOTE: This is the seventh in my "Hundreds of Hats Later: What I've Learned" blog posts. Next up: "First You Try."