I have always hated the fact that my starting chain was so raggedy looking. Each loop was a different size, some too large and some far too small. One day I was reading a pattern and just running the chain through my fingers without thinking. When I was done reading and went to continue crocheting, I noticed that my entire chain was perfect! Doing this with your first two or three rows of crochet, especially when you are new to it, helps even everything out so you don't get the dreaded rows that are shorter than the chain because your tension isn't right yet.
It really is a simple as holding your chain (with the hook still in) firmly in one hand and running your chain and/or chain with rows through the fingers of your other hand gently, but firmly. I am proud of my starting chains now and I used to hate doing them.
Try it. You'll be amazed! I was.