Even though considerable progress regarding the technical perspective on modeling and supporting business processes has been achieved, it appears that the human perspective is still often left aside. In particular, we do not have an in-depth understanding of how process models are inspected by humans, what strategies are taken, and what cognitive processes are involved. This paper takes a first step towards such an understanding and reports an exploratory study investigating how humans identify quality issues in BPMN process models. Providing preliminary answers to initial research questions, we also indicate other research questions that can be investigated using this approach. Our qualitative analysis shows that humans adapt different strategies on how to identify quality issues. Finally, we observed for different quality dimensions quality issues that were spotted by a large number of subjects (e.g., deadlocks), but also quality issues that did not seem to bother the participants...