I wrote too soon. Crocheting is very relaxing until you come to a big, frustrating knot in your yarn. Argh.
To prevent this, do a little preparation work:
One end of the wool will be coming from the center of the skein. Pull from this end and roll the yarn into a ball until you have unraveled and re-raveled the entire package. The opposite end of the wool will be wrapped around the outside. But it works easier if you pull from the center.
This exercise takes a little time, but will give you a chance to inspect the roll before you start crocheting.
Then you can start relieving stress as I promised in my previous post.