This idea that feeling an emotion is going to "harm" you, or that letting yourself feel your emotions without forcing the emotions to be what you want them to be, seems more detrimental to health than acknowledging and supporting oneself in emotions that come up.
The constant flood of stress chemicals and associated metabolic changes that accompany recurrent unmanaged anger can eventually cause harm to many different systems of the body. Some of the short and long-term health problems that have been linked to unmanaged anger include:
Digestion problems, such as abdominal pain
High blood pressure
Skin problems, such as eczema
How about "There is no situation that necessitates poking your own finger into your eyeball until it pops"?
Angry feelings are part of being human, especially when we feel powerless. One of the most important messages we can give our children is, "It's okay to be angry, but it's not okay to hurt ourselves or others." Besides giving children the right to their anger, we can help them find constructive things to do with their feelings. This way, we'll be giving them useful tools that will serve them all their life, and help them to become the worlds' future peacemakers -- the world's future "helpers."