I read this great article on PC Gamer about how developers use in-game descriptions to bring worlds to life: The Art of Flavour Text
“Flavour text implies two things,” says Alexis Kennedy, founder of Sunless Sea dev Failbetter Games and maker of forthcoming narrative card game Cultist Simulator. “It suggests it’s trivial and that it’s essential. On the trivial side it’s like grouting, it’s the bits you put in places so you’ve got something of value everywhere, something you put in between things that matter more. In the other sense, a work without flavour is tasteless, boring, so flavour text is what provides most of the sense of a setting, of being there.”
Check it out, it’s certainly worth a read.