Protocol analyzers, data generators, voice-over-IP (VoIP) testers, and other test equipment come with graphical user interfaces (GUIs). Generally, a GUI is all you need to run many test applications, ...
The (narrow but very important) problem: Test scripts used for version 1.0 of an application will probably break when applied to version 2.0 of that application. Testers try to edit old test scripts ...