You have to be careful there though. When it comes to computer software even perfect code can require a restart if different code on the same machine is interfering with it. The story has gotten much better but even now occasionally I'll have a reboot a Game or 3D visualization app because the graphics driver got wedged. It's not the applications fault it's the drivers fault.

The reason power cycling is such a useful tool is that most computer systems are running in an environment where the things outside of it's control way outnumber the things within it's control.