An unhappy employee can easily steal data
An employee can transfer confidential information to a USB drive when they leave, including client databases, emails, calendar appointments, and contact lists. This can have serious consequences for the firm. Imagine your Data falling in the hands of your Competitor! Scary!
Its not always about the loss of Data. Employees could even get their games and videos and play during office hours away from the eyes of their Manager. This leads to loss of Productivity.