I had to collaborate with some distinguished middle-aged scientists, and Fortran is what they spoke. And given how 'terrible' the code was, I developed great respect for their intellect - how they were able to get such results out of their tangles. (The moral of that story is: do not keep your intellectual property only in code)

'terrible' is the word we use, but they were not professional programmers (and had zero interest in the craft) So fit-for-purpose maybe, 'unstructured' but not 'terrible'.