Software that’a deferential to the user does not make decisions on the users behalf. It especially does not make destructive decisions. When presented with two distinct paths the software defers to the user to make the final call.
Software that’s deferential to the user doesn’t simply show confirmation dialogs for every interaction. Rather, it recognzes when an alternative exists. The user might not have been aware of it, has not considered or it might have consequences beyond the users expectation. It also understands that there might be more than one way of accomplishing something and that different user types might prefer different ways.
Defering important decisions to the user increases the users’ trust in the software. It also makes them more confident to use it.
While making sure that software is deferential, we must also make sure that software has common sense and that it doesn’t ask inane questions.
Deferential software might be informed about what days in the users country might be public holidays but would ask the user whether they would like to see this.