A chef trains his sequences over the course of his career thousands of times. After that every move appears fluid, always with a perfect result.
In the area of server administration it has been similar for a long time, but you can not only hire experts. Using Chef the sequence is written as code which, from this point on, becomes repeatable and versionable, producing consistent results. Provision one new server, ten new servers, a hundred new servers? No problem thanks to automation.