I think this scenario is very similar to what happens when you return from a life altering sojourn overseas. You have experienced new and wonderful things and you are brimming with confidence, sure that you can now tackle any obstacle, no matter how insurmountable. Yet, when someone asks you the inevitable “so what was the best thing you did on your trip?” you have more-or-less 30 seconds with which to give an articulate, engaging and meaningful response. That 30 second window is all you get, after which the other person will nod and tune out. When you’re sitting in a job interview and someone asks you the inevitable “why do you want this job?” you have about 30 seconds to dazzle them. Your answer needs to be valid, to the point and memorable. Prepare something in advance. Rehearse it with your partner or a friend, asking them for honest feedback. Focus on, not only why you want the job, but also (try to be subtle), why the company should want YOU for this job.