In this study, I seek to examine undergraduate STEM majors’ beliefs about and attitude towards mistakes in the context of counting. This is a particularly fruitful setting for such an investigation both because combinatorics is widely applicable to various fields such as physics, biology, chemistry, and computer science (Kapur, 1970), and because it is acknowledged by many in the field of math education research that students struggle with learning to count (Hadar & Hadass, 1981; Lockwood, 2014; Batanero, Navarro-Pelayo, & Godino, 1997). Specifically, given that students tend to display negative affect towards mistakes (Turner, Thorpe, & Meyer, 1998), despite the beneficial nature of mistakes (Borasi, 1987, p. 2), and that affective factors like attitudes and beliefs have a significant impact on students’ problem-solving activity (Carlson and Bloom, 2005), enumerative combinatorics is an ideal setting to study individuals’ mindsets (as in Dweck, 2006 and Boaler & Dweck, 2016). I helped to interview five students, asking them to engage in combinatorial problem solving, and reflect on their prior experiences with counting. I found that students’ self-reported mindsets and beliefs towards mistakes affected their counting activity. Furthermore, I also found evidence to support that the concept of mindset is a spectrum, rather than a dichotomy. These results serve to inform the existing literature, provide implications for the teaching and learning of enumerative combinatorics, and offer opportunities for future research.