Retail, easy. Like, I enjoy what I do for my job but the people that my store attracts, make it cumbersome. People coming to me all the time with phones in my face of listings to other stores thinking we have them, people impatient, people thinking we have everything and people being deliberately vague but getting pissed when you ask them what they mean.
Pharmacy. The patients that are the worst at managing their conditions are the ones you have to deal with the most. Add to that the issues that stem from insurance, addiction, neglect, or end of life care, it can be really tough.