Did Ewe Know?
The natural process of crocheting causes our fiber to twist.
This means that we are either adding more twist to the fiber, or we're actually untwisting it depending upon which end we opt to draw from. When this happens the fiber is either becoming more firm, or softer.
Most crocheters complain when a fiber feels too stiff (more twisting occurred) or when a fiber splits too much (untwisting resulted). The quickest fix is to use the fiber from the other end of the ball/skein.
The official names for the twisted fibers are "Z" and "S." If the fiber was spun clockwise then it's called "Z twist." If the fiber was spun counter-clockwise then it's called "S twist."
This is another reason why working test swatches is so important.