The parts of your (imagined, potential) customer's business process that makes him/her want to jam their sushi chopsticks up their nose and slam his/her head onto his/her desk.
The parts of your new technology you created that make your customers reach for the chopsticks. They're totally forgotten by you, because your kludge to work around them have become an invisible habit (unknown knowns).
FuctCo5K over 8 years ago Reporter: "What happened to this one, doc?"
Coroner: "Another double, trans-nasal frontal lobotomy. His pain point was trying to paste an Excel spreadsheet into a web-based ERP system."
Reporter: "What happened to this one, doc?"