I love pivot tables.
These days I only really ever have one spreadsheet design – a bunch of input type stuff, some reference stuff, a big database sheet and then a bunch of pivot table reports.
That design came into its own recently when a client asked for an urgent reporting change. Instead of reporting by reporting line as agreed, their client now wanted everything by geography.
A quick check of the database sheets showed geo was in there so it was the work of a few minutes to totally change the whole reporting.
Of course I still scratched my chin, drew a sharp breath and made it sound difficult and expensive!