Sometimes you need some "gray hair" on your project. After all, they've supposedly already seen it all, done it all, and made all their mistakes long ago - on someone else's project.
Gray hair is hair you can trust - and having lots of it (or for some, at least remnants of it) can be an advantage for us humble engineers. I was "blessed" with enough gray hair in my mid- twenties that I could easily pass for someone ten years older. More than 20 years later, I still claim to be in my "late, late twenties". It must be a genetic trait (the age claim I mean) - my mom still turns 21 again every March 6th.
This cartoon was inspired by a project with a particularly cantankerous owner's rep who insisted we put "more gray hair" on his project - after all, how could some young whippersnapper with a full head of "immature" hair, an engineering degree, and "only" a decade of experience with similar successful projects possibly be trusted?
Good news for that owner's rep: dealing with him caused the young whippersnappers to sprout a few gray hairs of their own.
