Why is "squaring" so prevalent in physics equations

(bolding mine)

This use of ‘naturally’ is why i love this board!

It depends. You can, to give one example, write any trig function as an infinite series, so any equation with a trig function could be written in such a way that the answer to your question is infinite. To a certain extent the way we choose to write out the equations is arbitrary-- based on the coordinate system we use or the mathematical formalism we employ.

Reminds me of a story from one of those “overheard comments” books from some years ago. A student is crossing the quad in a Cambridge college and sees two dons walking towards him, one talking vigorously and ticking off points on his fingers. As they pass, the student overhears just " … and ninthly …".