The work was extraordinarily tedious, error prone, yet business critical. We had to keep shimming in new parts of the system, while keeping the old system afloat. While the system was always on the verge of imploding, from the outside, it basically appeared to work, which kept the project chronically understaffed.
I have a lot respect for anyone who aggregates time critical production data from different sources. The nature of the work makes it extremely stressful, yet surprisingly easy for outsiders to underestimate.