Why do insiders pose such a significant threat to an organization?

Why do insiders pose such a significant threat to an organization? Find examples to justify your position.
What are the main problems with preventing social engineering in an organization? Give examples to support your answer.
Why is it necessary to define enforcement policies for security rules in an organization? Why is it necessary to consistently follow through on enforcement?
What is the benefit of including security consideration in an organization’s culture? What is the best way to get buy-in from the employees?
What factors should be involved in deciding on a delivery method for an organization’s security training? Give at least three factors and the trade-off that is associated with limitations on each of them.