> - Complicated business requirements ("do this every second Tuesday if there is an R in the month, but not if the customer is using the US VAT system and not i

> - Complicated business requirements ("do this every second Tuesday if there is an R in the month, but not if the customer is using the US VAT system and not if the product is a type of cake") And then you realise there's no consistent definition of "cake" in the system. And when people in the business say "US VAT system" they actually mean "Regulatory system XYZ", not actually anything to do with the US. Sigh.