In my opinion, anger has some reason behind it. As opposed to many people I am not hostile to anger anymore.
When do you feel angry? When someone helps you? When you help someone? When someone does a good job? (then it will be jealousy if you have any emotions at all!)
So, whenever and wherever you feel angry there's a reason behind it. So, it needs to be expressed to correct the situation. However, you should consider the mistakes of innocents like kids, and so on.