Fair is a tricky word. It means things are done that are decent and are acceptable to the people or the parties concerned. In dividing profit in a business venture, for example, it will be fair if the division is as agreed upon and it is satisfactory to the parties involved in the undertaking. Once there is a break of promise and things are different from the original agreement or deviating from the normal practice, a sense of unfairness will emerge and can become the point of contention such as a law suit in the court of justice or the other party may take law into their own hands. Tradition and convention will help mitigate such conflicts such as the commission fee for land sale generally will be 3% or royalty for a book published will be 15%, for example.