Emergence
"Emergence is a characteristic arises as output of a system, that could not have been predicted from an analysis of the individual parts which comprise the system. "
This is why the study of systems is important. When something good happens, everyone wants the credit. In a linear thinking world each component piece of the system sees their contribution as the "key to success", when in reality the success was most likely emergent and could not have happened without the interaction between the constituent parts. Conversely when something bad happens, everyone wants to lay the blame elsewhere. Again the reality is that the unintended consequence probably was an emergent quality resulting from the interaction between parts of the system.
Only by studying the interactions between all parts of a system (system thinking) can a true understanding of the causality for success or failure be achieved.