Using Debbie's example of a child running through the house with a pair of scissors...

I've seen so many new parents stop that child by yelling at them, getting angry and sometimes even spanking the child. That's not necessary! You may need to take a hold of them suddenly and with a certain amount of force, getting their attention in a very dangerous situation, but you take the scissors away from them gently and explain, maybe even demonstrate how dangerous their actions are... but you tell them with kind words and a kind tone of voice... never forgetting to hug them and tell them how much you care for them.

It's almost certain that they won't listen the first time, but there's not need to get angry... or at least show that anger in it's raw state. You keep telling them as often as they need it... maybe to the point of not allowing them to play with scissors, for their own good... and you tell them so. You tell them or another person in the same words you would like to hear the same admonition.