I recently had to install some software that wouldn't run because I gave my SQL Server instance a descriptive name. There was no (or at least not easy) way to get it to use anything other than the default name "MSSQLSERVER". At the same time I removed my SQL Express which my Azure storage emulator used so I had to fix that one too... At least that is fairly easy: DSInit /sqlInstance:.
Also love it when a product destroys an instance thinking that its product will be the only db using that instance, in this case they updated the documents right after I had already killed a bunch of production db's. In the preprod enviro they setup up a single instance/single db so the impact was unkown.