But if the interviewer is trying to have an interviewee sell them a product they up front know they're not even mildly interested in buying (as is probably the case for most of the HN crowd, we'd probably never actually buy a pen - digital for almost everything, free pens from wherever for whatever might need writing), they're either cynically hiring for a boiler room operation or doing it wrong.
In this exercise, you know nothing about the pen, so obviously it is not about the pen - you will not sell the pen if you focus on the characteristic of the pen, you need to find a need for a pen within the interviewer which is the 101 of a sales position. Like those programming questions - of course there are better way to find prime numbers or whatever you need to code - you are not here to discuss the math stuff, you are here to show you can write a few lines of code with a structure, solve a problem, ask the right question, ...
1. store info of the pen not being memorable (can use that later as per the transcript)
2. Ask for what typical activities they use a pen for. Then try and describe back to them why the pen is important based on those events. If they respond 'I don't really use a pen much'....well that might be a little harder :)
Overall an interesting transcript. I haven't studied sales much so not sure about the theory behind it all but the example seems very good. Though I'm sure there's other ways to succeed at the task without necessarily following the OP's principles exactly.
Which I suck at, for the most part, and have never put much effort into getting better - and that's why I'm not in sales. But you don't need to be good at something to understand in general terms how it works.
* Q: Do you remember what kind of pen that was?
* A: Yes, it was my favorite pen that I got from my wife for our anniversary
* Q: Do you remember why you were using it to write?
* A: I signed a credit card receipt in Walmart.
Easy-peasy.
Do you take notes?