The highly competitive academic research environment selects for faculty who are 100% dedicated to their research and thus able to publish the most and bring in

The highly competitive academic research environment selects for faculty who are 100% dedicated to their research and thus able to publish the most and bring in the most grant money. Such faculty, of course, expect the same dedication from their graduate students. The worst nightmare for a researcher is to have a graduate student that makes slow progress, constantly depends on the researcher for oversight, and produces few results of value. This graduate student is wasting time and resources and has little hope of successful completion. The more assured a researcher can be that a student is completely dedicated to research, the more likely he or she will be to accept the student. For this reason, it makes sense to only list your experience in the field on your CV. But if, once you enter, you are able to work efficiently and produce good results, it should not matter what extracurricular activities you participate in. If your adviser told you to quit your part-time job, I think that it is more likely that he's frustrated by your lack of progress than that he is embarrassed that you have outside interests.