[leephillips]

“If you write a math formula, how is writing "side_a" or "phi" worse than "a" and "p"?”

When you pick up your pencil to do some manipulations on that formula, you’ll wish you’d chosen the one-letter variables. Also, single character variables, perhaps with different fonts, subscripts, or other decorations, make it easier to see the structure of the equations. That’s why we use them in math.

For those of us who use a pencil to manipulate our code, to see how it might be transformed, the value of short variable names is the same—we’re often going back and forth between code and math. That’s why languages like Julia that let you use Unicode identifiers are so cool.