[TrianguloY]

Not only that, but when you save something to a variable the reader needs to remember it in case you use that variable later again. For me personally that's exhausting.

I've seen streams-like code with a variable for almost every step, immediately used the line below. I can understand when the reason is to "explain" the meaning of the intermediate step...but even so a comment is far better on my opinion.

I always try to inline every 1-use variable/method, unless there is a good reason for not doing so.

[InitialLastName]

I feel like Raymond Hettinger's guideline that line complexity should be scaled to the limitations of human working memory, so should be limited to 7(+/-2) tokens [0], is a good compromise. This leaves some margin for nesting, but keeps in mind the capacity of the human brain to understand what a line is doing. If you can explain what the line of code is doing in a single sentence, you can probably also find a way to either name the variable sensibly or factor the code so that your step is a (well-named) method instead.

[0] https://en.wikipedia.org/wiki/The_Magical_Number_Seven,_Plus...