I once was called into an emergency meeting by the CEO of the company I was working for the time. When I entered the room, all of the top brass were seated around the table, some visibly agitated. The CEO proceeded to hand me a single black whiteboard marker as he stated "the fate of the company depends on you". The problem was outlined by a fellow engineer and it was explained that I had 10 minutes to solve it, or we might risk going out of business.

With that, I took a deep breath and went to work furiously scribbling away on the board while everyone watched with anticipation. As I closed the final bracket, and stepped back to examine my work, audible gasps could be heard from around the room. The grizzled old CTO whom everyone was a little scared of broke the silence at last: "God dammit, Mark!" I caught a few nervous glances from some of the less technical folks. You could hear a pin drop when he continued:

"you just saved the god damn company!"

A slow clap started, and soon everyone joined in with a round of applause and cheering. Over the outburst of joy and adoration the CEO shouted to one of the developers who had gathered outside of the conference room, "get this code into production!" Soon the whiteboard was being whisked away by a group of smiling engineers as they navigated with great purpose through a sea of high fives and back slaps.

And then, with a twinkle in his eye, the CEO shook my hand, and pulled a crisp $100 bill out of his wallet. As he handed it to me, he said "I knew from the moment I heard about your interview that you would be a great asset to this company, Mark. Go home and relax for the rest of the day and take your wife out for dinner tonight. You've earned it."

So you see, being able to solve complicated problems on a whiteboard in a crunch time is a valuable skill.