The LaTeX software is known as a high quality typesetting program. The reason why LaTeX generated documents are described as high quality is because they are looking the same like hand-typeset documents created 200 years ago. To understand LaTeX better we have to describe what classical hand typesetting is about.
Typessetting 200 years ago was at first the art of creating fully justified text. The interesting fact is, that this formatting style is only seldom described in the literature. MS-Word has a simple button to activate it and LaTeX is using this formatting style as default. So the user has no further explanation why this is needed.
Fully justified text means basically to adjust the words on a line so that the right and left edge are straight. In case of hand typesetting this art was very complicated to realize and the main reason why it takes so long until the metal characters are sorted on a page. The main trick for created adjusted text lines is to use glue between the words.
In the past, all the newspapers were typeset with this formatting style. What the manual typesetter were trained is to realize this unique shape. From a technical perspective it is possible to create flush left pages with manual typesetting as well. It would be even a bit more economical. But nobody has done so. A closer look into old newspapers will show that 100% of them were typesetted with fully justified text.
The idea of LaTeX is to imitate this formatting style. A standard LaTeX generated document will look like a newspaper which was manual typesetted in the past.
It is not very hard to guess what the opposite of fully justified text is. Flush left text is equal to missing typesetting. A flush left formatted text looks very different from what is used in newspapers in the past. The main reason why LaTeX generated texts are looking all the same is because of missing flush left formatting. The typical latex user assumes that it is prohibited to use a flush left formatting style.