Quantitative social scientists have adopted the positivist epistemology and methodology of natural sciences, seeking objectivity, generalisability, and neutrality. However, in social sciences -- unlike in natural sciences -- humans are both the investigators and the object of investigation, leading to intricate interconnections between researchers and participants. This paper presents challenges and opportunities of positionality in quantitative social research. Positionality can uncover gaps in the researcher's knowledge, which may feel unusual and particularly uncomfortable from the positivist point of view, but which can in turn reveal unanticipated opportunities. This postpositivist argument is informed by a mixed-method project exploring Chinese and non-Chinese speakers' perception of emotions expressed in Mandarin, conducted by an L0 researcher -- i.e. one who is unfamiliar with Chinese languages and culture(s). This particular position stimulated reflexivity and instigated the inclusion of other subjectivities in the process. Accordingly, this project illustrates both the challenges and advantages of such undertakings. Once researchers acknowledge (the influence of) the position they speak from and what they do or do not share with participants, they can overcome their 'knowledge gaps' by adopting suitable research methods and involving 'knowledgeable collaborator' in the process.