Over time in a well-maintained project there's a tendency for these to clean themselves up, and a feeling that the codebase is in good shape emerges.
Variables become clearly and simply-named, the code starts to read more like a hybrid between a human language and a programming language, and the formatting and syntax become - generally - more straightforward and less 'clever'.
Ideally the patterns and algorithms also gravitate towards readable and efficient patterns (using generators, dunder methods, collection types, and so on where appropriate) until the code feels pleasant to understand and modify.
What's your favourite language for intuitively assessing code quality, and what are the indicators and criteria that you think you use?