Since you use the
academic-graduate tag, I assume you're talking about the second year in a graduate (presumably PhD) program. Congrats on making it past the qualifying/comprehensive exams!
In your second year and onwards, your focus should be on developing your own research agenda, and the courses you take will partially help you achieve that end. Your research will inevitably be built on existing work by others. The field courses (i.e. labor, public, development, or whatever else that's offered at your department) will help you survey the literature in the respective fields. In doing so, you will get an idea of what has been done in a particular field, and what remains to be done to close any gaps in our understanding of topics in that field.
Of particular importance in these courses is methodology. For example, you may not be interested in the issue of gender pay gaps, but by reading papers on that topic in your labor course, you may learn the tools of diff-in-diffs or RDD, which you can later apply in your paper on the effectiveness of political campaigns. Or perhaps you are not that into the topic of executive compensation, but your labor course may introduce you to the principal-agent model, which you later realize can be readily applied to studying the relationship between foreign aid providers and political elites in developing countries.
Ultimately, you need to have a clear idea of what you would like to do in terms of research, and choose your field courses accordingly. If you don't find labor/public/development sufficiently stimulating, go talk to the faculty in other fields in your department and see what they are working on. You may be able to do a reading course with them on papers and topics that you're truly interested in. Your department chair can probably refer you to the right faculty if you have a discussion with him/her about your current conundrum.
Of course, if research is just not your thing, it's more than okay to call it quits. In fact, it'd be better to quit earlier than later, since you'll start accumulating human capital in the other areas sooner (and waste less time on a non-productive activity).