I did some work at a distribution company where 25 years earlier someone said orders would be either "machine" or "parts". Everything was built on that, and unt

I did some work at a distribution company where 25 years earlier someone said orders would be either "machine" or "parts". Everything was built on that, and until very recently when they spent hundreds of millions to replace with an ERP, it remained. Want a PC with an incompatible separate part? Can't be done. Create two orders please. Unrelated but same place, during some profiling I wondered why the massive server spent 1% of its time on a user table scan. It was converting the entire user base's username column from varchar to user_name()'s nvarchar on every interaction with the DB. These guys (and the database optimiser) were all really solid, but stuff sneaks in.