I feel seen :-)

In my first job I updated someones (doing a PHD in fluid mixing) Fortran code.

The original software to run an experimental rig just put up a ? prompt and you typed numbers in to drive the experiment.

You had to memorise which number was used for what and at which point you had reached.

I updated it to prompt the user and at every step display what options where available and also allowed you to go back a step.

I even went as far as to use Mixed Case Hollerith segments!