We all have those snowflake environments that are built using Chef, but we're not comfortable with running the Chef client anymore. We know that some cookbooks have been enhanced but never tested against this specific environment. The risk of bringing it down by a Chef client run is pretty high.
However, even though we do not dare do a full Chef client run, we might need to run, for example, the users cookbook, in order to add a new colleague to our snowflake environment. This is where Chef client's feature to override a run list to execute a single recipe comes in very handy.
Note
Don't overuse this feature! Make sure you fix your environment so that you're comfortable to run Chef client whenever you need to!
To follow along with the following example, you'll need a node hooked up to your Chef server having multiple recipes and/or roles in its run list.