This is absolutely it for me. It's also why I like paragraphs to have some level of spacing between them.

I'm currently reading a book that has quite minimal indentation on the first line of a paragraph, no spacing between, small font, and justified text. Every page is just a wall of text. It makes it noticeably more tiring to read than others that I've read recently. It seems to be a trend in more serious historical tomes. The last one I read, the Beauty and the Terror, was similarly typeset.

It's one of the reasons I like reading on my kindle.