It works, and that is the problem

If shouting did not work, nobody would do it twice.

You shout, the child stops, and the noise in the room drops. That is a reward, and it arrives within about two seconds, which is exactly the timing that makes a behaviour stick. Your shouting is being trained by your children, reliably, several times a week.

Nothing about that is a character flaw. It is the ordinary way any behaviour gets learned, pointed at the wrong outcome.