And that is the point.
Things happen.
If they are going to happen, the question is how much one is willing to embrace Things Happening.
Games or tables that use Fail Forward or Success at a Cost techniques, or that generate Complications (using generic terms - each game can have different names for these) embrace that Things Happen to the point of making them part of the process of play.
Which I think is an important point - these are not the GM doing something outside the scope of their role - they are adopted into the role, explicitly.