People are generically bad at reliably setting states. The problem isn't so much that someone failed to do something (an action) but that they failed to notice

People are generically bad at reliably setting states. The problem isn't so much that someone failed to do something (an action) but that they failed to notice that the action was not done (the state was wrong). Often times people forget the "check" part of the term "checklist" and treat them as a list of things they must do. The result is less reliable because it is easy to skip a step, even if you end up ticking a box. A checklist involves two steps, first doing the thing (possibly from memory) and then consulting the checklist to see that the appropriate state is set. This is a particular issue for programmers as programmers are constantly involved with lists of actions that are performed in sequence. As a result there is a tendency to let the list run the human in a way similar to how a computer runs a program. Computers are way better at states than humans are however...