Welcome, everyone, to the grand show of reality! - some assembly required.

 

The Pitchman (Standard Physics): "Welcome, everyone, to the grand show of reality!"

Step 1: The Foundation.
First, we must build our stage. For the floor, we'll use this random plank we found; we'll call its length a 'meter.' For the weight-bearing pillars, we'll use this lump of metal we have; we'll call its mass a 'kilogram.' And to time the show, we'll use this grandfather clock that ticks in 'seconds.' Now, I must be honest with you—these three things have absolutely nothing to do with each other. They're arbitrary. They're crap, as you say. Are we all clear? The foundation is a wobbly, uncoordinated mess. Excellent.

Step 2: The Performance.
Now, watch! We'll put two of our 'kilogram' pillars on the 'meter' stage and observe them. Look! They're attracting each other! But when we try to calculate the force, our numbers don't work. Our crappy, independent units don't line up with this beautiful, universal dance. The math is a disaster.

Step 3: The Grand Reveal!
But wait! We have discovered... a Mysterious and Profound Universal Constant of Nature! We shall call it G! When we multiply our calculation by this magical number, the math works perfectly! It is a deep truth of the cosmos, a fundamental property of gravity itself! Isn't it breathtaking?

(Whispering to the side): Please pay absolutely no attention to the fact that this 'magical number' is, in reality, just the specific, boring conversion factor required to fix the wobbly, uncoordinated, crappy foundation we started with. It is s a mystery. Admire its mystery! Give it a Nobel Prize! "