The system feels lightning fast, until a stale cache invalidation issue serves users their ex-partner's billing information.
"Answer delivered in 12 milliseconds. >> From yesterday. >> Fast, maybe true. [music] >> Index it or suffer. >> Truth has terrible latency. tinycto.tv [music] The system remembers. >> Ha."
This happens when teams use Redis or Memcached as a crutch for bad architecture, leading to split-brain scenarios where the UI and the database disagree on the truth.