Keep your answer thoughtful and avoid sounding cynical about the challenges or difficulties you face in your work as an HR professional. Try to approach this question realistically while still showing a positive mindset. For instance, perhaps the most challenging aspect of your HR management job is the termination meetings you are responsible for leading. Yet, you do your best to ensure the terminated employee leaves the meeting feeling supported and respected. Discuss the challenge, and then focus the bulk of your answer on the solution you have found. This approach will show the interviewer that you view this challenge as a learning experience and not one that leaves you feeling defeated.