Why is TeX balky?

TeX calculates and compares values, on which words, images, tables are all put onto the pages of a book. It usually works well. But, especially for the books not written in English, we often need to change its behavior. Some programmer will try to change values or functions (macro) which used to manipulate these values, and fail, and hate the program and its author.

However, I suddenly recognized today that the TeX features are all associated to work with values representing the beauty. I mean, the beauty which Knuth thinks (or may feel) to be. And, of course, the beauty is hard to determine logically, so TeX calculates it with a ton of parameters working reciprocally, interacting with each other, and affecting to the whole system independently. As a result, it is beyond human understandings, as is the way with some other beautiful things.