Rules exist for a reason. They give us guidelines to follow, and they show us how to get from point A to point B with minimal fuss. They keep order and prevent society from falling into chaos. At least, most of them do.
Some of them don’t. Some rules restrict us, blind us to possibilities, and prevent creativity. I see this all the time when teaching students to write. They have had the five paragraph essay format drilled into them so deeply that they can’t comprehend any other ways to write; they can’t even conceive that there ARE other ways. They know the rules of writing, and they have to follow them, even though it makes them hate writing papers. They know they are constrained, they know they’re in a cage, but since they can’t see the bars, they can’t escape.