This part is true for any software developer: "Nothing is quite so humbling as being forced to watch in silence as some poor play-tester stumbles around your l

This part is true for any software developer: "Nothing is quite so humbling as being forced to watch in silence as some poor play-tester stumbles around your level for 20 minutes, unable to figure out the "obvious" answer that you now realize is completely arbitrary and impossible to figure out." If you want to build software that is easy to use, you need to watch people use your software.