...such as? All jobs I can think of -- even the most low-status or menial -- requires a certain skill and can be done with varying levels of quality.
All jobs I can think of involve some sort of outcome that is desired by the one purchasing the work. Furthermore, that outcome can be of insufficient quality and therefore rejected by the purchaser, or at least not fulfilling the needs they were expecting to have fulfilled.
All jobs I can think of involve some sort of outcome that is desired by the one purchasing the work. Furthermore, that outcome can be of insufficient quality and therefore rejected by the purchaser, or at least not fulfilling the needs they were expecting to have fulfilled.