Organized Chaos
The phrase “organized chaos” is used in reference to quantities of complex and disorganized work or activity that is managed well by capable people. It is said in a half joking way about something that can, in fact, be managed well but requires a person with a certain skill set or talent in order to do it successfully.
Example:
Each day of Session is extremely busy, there are a thousand moving parts, and it can be extremely difficult to keep up. Katherine always says that Session is just organized chaos.
Note: I thought that I made this term up but I heard someone else use it not long ago. Anyone who has experience Session could easily coin this term on their own. It is a unique experience and the phrase organized chaos describes it well.