The LaTeX community claims indirectly that only fully justified text looks clean. The TeX engine tries to create such appearance really hard. Advanced hyphenation, spacing and even intra word spacing is used to make sure that each line has a straight edge on left and the right side as well.
The interesting situation is that the average reader doesn't care about this feature and a causual look at the document can't tell if it was formatted in fully justified mode or not. The example screenshot shows a document which was formatted left justified without any hyphenation. In spite of this absence of high quality formatting, the right edge looks reasonable well adjusted. Sure. It is not forming a perfect line but the document doesn't look very uncommon or even chaotic. The thesis is that the goal of creating fully justified text is maybe no longer important?
In the current example an unsharp fiilter was applied to the image so that it is no longer possible to recognize each words. Instead the reader will perceive the document from a distant view. The interesting situation is the right edge looks reasonable well formatted, even no formal fully-justified mode was applied. It seems that on the average a simple left-justified line wrapping algorithm results into a near right edge even without adjusting each line with inter word spacings. Is the TeX internal algorithm for word spacing an example for over engineering in a sense that in the reality nobody needs such formatted documents?
From a technical perspective, a left-justified document has the same appearance like a text rendered in a browser. That means, the spacing between the words is always the same and if the line is full, the word gets wrapped into the next line. This sounds a bit un-typographic but it results into an easy to read text.