What would you include on your resume if you had to fit it onto a 3 by 5 index card?

I was asked multiple questions throughout the different interviewers, but one that stood out to me was to explain a time where I faced a tough customer who was unhappy. I had a few of these experiences when I was a retail intern in the previous summer for TechTronic Industries. This stuck out to me because I have never been asked that before, and they asked how I handled it.

What can you bring to the ISN team? What leadership roles have you been apart of ?