The interviewers ask this question to see what you like least about your chosen profession and where you may have challenges if accepted into the residency program. You want to make sure you describe your least favorite part as something the interviewers can identify with, showing you are only human. Some examples could be your least favorite part is losing a patient, having to deliver bad news to a patient and their loved ones, or having a patient refuse life-saving treatment. After describing what you like least, end on a positive note by explaining how you work through this challenge.