The One Lens Every Photographer Should Have and Use: the 50mm

If you are stranded on a desert island and can only have one camera lens with you, which lens would you choose? If your answer wasn’t, “a 50mm (or 50mm equivalent lens),” then you might be wrong. The 50mm prime lens is the one lens every photographer toting an interchangeable-lens camera should own… and use.
Why? Before I tell you all the reasons, I will tell you a sea story. But, before that, know that in the world of different sensor (and film) sizes, there are different equivalents to the 50mm lens. More on that later but, for now, I will be referring to full-frame digital and/or 135 format film. As the reader, please press the “I believe” button and keep on reading.

My Personal Journey

My father is a great photographer. He grew up working in a camera store in New Orleans. He has wielded a Leica rangefinder since long before I was brought to life. When I started my SLR photographic journey, he bought me my first “real” camera, a Nikon N6006, and a Nikon 50mm f/1.8 lens. He insisted that the 50mm was the best lens with which to learn.
But, this 50mm prime lens felt limiting. I wanted to get closer to things without moving my feet. It wasn’t long before I had recycled enough soda cans to buy a cheap 35-70mm zoom lens. And then I got a 70-210mm zoom. Soon, the 50mm f/1.8 was doing nothing but keeping a small circular region of my bookshelf from seeing light.
For decades, the zoom lens served me well. But, years later, when working on my Master’s thesis, I rediscovered the lens for many reasons (see below) and have since gravitated back to a battery of prime lenses. Now it is the zoom lenses that are keeping areas of my bookshelves from getting dusty.

So, what makes the 50mm the one single lens every photographer should own (and use)?