I did an AOP project back in ~2007, where we used crosscutting to separate the frontend from the backend, due to the belief that in the future we would swap out

I did an AOP project back in ~2007, where we used crosscutting to separate the frontend from the backend, due to the belief that in the future we would swap out the thick client frontend for a web client. It was kind of a nightmare (to put it kindly). This was an insurance app where updates in the frontend would automagically be pushed into the backend algorithm, which would automagically push changes to the frontend, which would automagically push changes to the backend... The client also didn't pay for regression tests (2007 was a long time ago!) so basically every week it infinite loop locked in some new and undebuggable way.