What software is the simplest?

It depends the way you look at it. From the programmer point of view, that could be defined as a simple software if it involves less complexity interms of program level design, programing language  / tools & coding etc. 

And from user point view, simple softaware is supposed to be user friendly,felxible,versatile and extent to which customisable etc

the simplest software for cabinet production and output for most CNC machines is polyboard it is a parametric software and it is very very very easy .

thanks 

i think dolphin cam is easy for new users it for near about all famous  post processors.actually you never mentioned the field (scada ,plc ,cnc or what )

it is my guess due to nature of your work.

Each program merhas afavorite programis consideredeasy but for the programmershould befamiliar with allthe programs and mustmake it clear that there is a programe asy and difficultprogram

to be honest, within these current times where every organization wants to protect digital information, the best software is the one that is understood by every person in the organization.

Based on the application and usage the software differs. According to the experience of the persons and the capability the software toughness depends. The MATLAB, AUTOCAD,are some easy to observe and design.