Simulation software used for modeling has become as ubiquitous as computers themselves. Despite growing reliance on simulation in educational and workplace settings, users encounter frustration in using simulation software programs. The authors conducted a study with 26 engineering students and interviewed them about their experience learning the simulation software Arena for optimization modeling. These students experienced frustration with the process of learning to "think" like the simulation software. Students explained their difficulty with learning the software in a way that implied human dialogue with a machine and negotiation with Arena in an attempt to overcome this frustration. Rather than being gender specific, frustrations were experienced by most male and female students equally, specifically those who held a perception of difference between human and machine "thinking." The authors contend that communication difficulty with the embedded assumptions of the software is the source of frustration rather than deficiencies of users. (Contains 3 notes.)