The worst experience I had was with a telecom company. They had an internal web app that allowed them to upload a gigantic CSV file with millions of records from new phone activations. The web app took 59 minutes to process it!

The culprit: a single 30K .js file with one function, more and more recursive functions, and deeply nested if/else statements, up to 10 levels.

We spent one month undoing that Gordian knot and got the same process down to less than a minute. With AI, we probably would have done it in less than a day, and with a better programming language, probably even faster.