I began my software development career during the dot-com boom in the late ‘90s. One of my first projects was building an online banking website for our credit card product. We were trying to connect users to our mainframe over the Internet, which was cutting-edge back then.

I still remember one of our early meetings with the mainframe team. The web team and the mainframe team sat across from each other, talking about how we could make this whole thing work.

The mainframe folks focused on the reasons why it wouldn’t work—pointing out the risks, the challenges, and how much time it would take. On the flip side, the web team was focused on how fast we needed to move, how customers were asking for this feature, and how it could make life easier for our customer service team.

As we worked through the meeting, I noticed something that stuck with me. Everyone on the mainframe team was writing with pens, while everyone on the web team had pencils. It hit me that their choice of writing tool was kind of a metaphor for how they thought. The pen represented a mindset that was fixed, permanent, and unchangeable. The pencil, on the other hand, symbolized flexibility and adaptability, designed to be erased and revised as needed.

Now when I’m feeling resistant to an idea or project I ask myself “Am I thinking in pen or pencil?”