Many security policies are mandated by outside forces, government and industry, rather than the internal IT department. Most of these can not be changed to make it "easier" for an employee to do what they think is best. Our company has to work with regulations from the credit card industry, health care industry, and a number of state and federal agencies.
A lot of these restrictions are to keep anyone from uploading data on our computers or accessing data their job does not specifically require. While we do have latitude in some areas as to what programs the users can access, other areas are totally locked down to approved apps, especially with the PCI compliance. Things like DropBox and a number of other sites are totally off-limits.
Other restrictions we have to implement prohibit the use of cell phones or any other personal electronics in the office. Again, this is more to protect the information the employees have access to, rather than draconian rules we make up because we can.