https://www.paramountplus.com.au/training/dealing-with-difficult-people-training/

The most difficult aspect in any business, small, big, old, or new, is often the management of people. In most cases, the hardest businesses to handle are those that rely heavily on customer relations and those that require a large number of employees to operate. Many aspects of business can be controlled or predicted except the capriciousness of people. In fact, the father of quality management, Edward Deming, is quoted to have said that “people can face almost any problem except the problem of people”. People can deal with almost anything in their lives it seems, from sickness, the loss of a job, declining business, and even natural disasters. The one thing that people cannot seem to deal with is difficult people in their lives and in the workplace.