There was once a lion without a roar. The lion had always been this way, he had never been able to roar. But no one on the plains knew this. Since from an early age he realised he could not roar, he had learnt to talk softly with everyone, and to listen to them. He learned to convince others of his point of view without having to raise the volume levels. This won him the affection and trust of all the inhabitants of the plain. But one day the lion spoke to a pig who was so stupid and stubborn, that the lion could not find a way to make the pig be sensible. He felt a strong urge to roar at the pig, but the fact that he could not made the lion feel at some disadvantage. To try to solve this problem, he spent a few months inventing a roaring machine which he could use whenever he might need it. A short while after completing the roaring machine, the stupid and stubborn pig turned up. He annoyed the lion so much that the lion used the machine. It sent out a truly terrifying roar. "Grrrrrrrrrroauuuuuuuurrrr!!!"Not only did this give the pig a terrible fright, it also shocked all the animals on the plain. So much so that for months none of them dared to come out. The lion became sad and lonely, and had plenty of time to realise that he didn't need to roar in order get others to pay attention to him. Without knowing it, his lack of a roar had made him good at talking to others and convincing them. So, little by little, using his kind and cordial tone of voice he managed to restore the animals trust in him, and never again did he consider returning to roaring or shouting. 
Shouts and threats are not the best way to make friends, nor to get what you want. 