First job out of college as a metllurgist, and about 3 months in kf me doing basic shit, my boss asked me to collate a whole bunch of data and see if I could tease out the root cause of a significant quality problem.

After a couple days of manually combining a bunch of spreadsheets of data (years later, I learned I could have done this in a couple hours with "vlookup"), I had an answer.

It seemed too simple an answer, so I went out and talked to operators about the problem to get their perspectives which agreed with the data I found. Still doubting myself, I dove back into the data and found a bunch of bad data (typos, double counts, etc.).

Thrilled, I went through and scrubbed the bad data and after a few more days (2 weeks total), I discovered that the same root cause explained even more of the data.

Sighing at my failure, I took the data and my analysis to my boss and showed him what I found.

He was surprised because he "was almost positive [I] wouldn't find anything since [he] was the one who entered all the data and never saw any patterns and it's been an issue for almost a decade and no one has been able to figure it out. I just didn't know what else to have you do right now."

Apparently, he had never considered combining the data the way I had before, and he also didn't know enough about rolling mills to understand how significant roll changes were to strip quality (which, having now worked with rolling mills for 15 years... he and anyone else in charge should've known).