KHAN
Computers and FBW have been installed to assist the pilot to fly the aeroplane safely within it's design spec and help reduce the workload. They are intended to keep the ac within the the flight envelope and keep the pilot and machine safe.
You still have the option to overide and fly manually, but some computer functions will prevent you doing anything it considers dangerous or out of limits.
Unless in an emergency, why would you want to do this anyway unless your getting bored, so why should you be flying in the first place?