They do have it. Quotes (esp multi-paragraph ones) are usually indented another level in. So are nested lists (imagine if lists on different levels of nesting o

They do have it. Quotes (esp multi-paragraph ones) are usually indented another level in. So are nested lists (imagine if lists on different levels of nesting only used different bullet characters). So are mathematical formulae. Or table of contents. Or bibliographic references. Tables in general are a special case of horizontal spacing that matters. Figures and images in text. It's not as common because writing is not all hierarchical all the time (or at least, lots of space would be wasted if entire chapters/sections were indented one level extra), whereas programming is heavily hierarchical with shorter "blocks". Horizontal indentation is the most common way to express that hierarchy, including in programming languages that use block termination indicators — indentation is used to help humans parse the code, termination indicators are there to help computers parse it. You are making it sound as if you are not making use of indentation when programming: I thought the only complaint was about it being significant.