[Koyuki]

You didn't fail, Having children is the most wonderfull thing in the world, you're related to them in feeling and biologically. That's why i think you must increase the communication intensity in your home. If you feel sad with their act tell them you feel sad with what they're doing and you expecting them to behave.
Talk for every simple thing, like if you will them to wash their plate after dinner and they didnt obey, just tell them that you would be happy if they do it. Look into their eyes when you say it like you're diving into their feeling , you say it and you mean it. Even when you give them a time up.
So i think improve the communication.