Prettyness is important, but legibility is more important.

I don't know why we're still obsessed with right justification? In 1450 it made a lot of sense to try to squeeze the most text on a page, but today it isn't?

Justify is not only useless but it's also responsible for creating all those white spaces of various length, which are annoying enough by themselves, but which can also create "rivers" which become an incredible distraction.

The first thing I do with a new ebook is to modify it in Calibre so that it's left-align instead of justify.

Maybe "pretty" is a solution, but non-justify is simpler, and readily available.