I use graphs because we have a case where we need to schedule actions/programs but they themselves have "ingredients" or dependencies in a wild arrangement. So a topological sort of a graph is incredible to solve this and run those actions in order.
Largely because of taxes. Brazilian taxes are extremely high.
http://www.quantocustaobrasil.com.br/site/downloads/impostos...
This table is in Portuguese but it's easy to understand. The second column means the tax percentage of certain product / service.
It's published by the union of Ministry of Finance's workers.
That reminds me of a (satirical) development process we have here in Brazil. It's called goHorse Process.
The site is entirely in portuguese but with a little translation help you can have fun too.