* Indenting consistent with the curly braces, and well enough defined that when you remove an outer loop and want to unindent the code from that block, you don't have to do it by hand.
* A one-line code change doesn't bring with it a 500-line style change because the file passed between people with different style tastes.
Unfortunately, it's often difficult to achieve these modest desires without someone also wanting to limit line lengths, ban the ternary operator, ban nulls, and so on...