What started as a simple button morphs into a sentient ecosystem after weeks of uncontrolled scope creep.
"Just one more thing. That thing needs storage, queues, monitoring, and support. I can scale that for a price. The road map has entered invoice form. tinycto.tv [music] The system remembers. Ha."
This happens when product managers and engineers fail to define a strict Definition of Done and allow 'while we are at it' additions to hijack the sprint.