Rage Versus Healthy Anger
Yes, healthy anger. I tend to think that just about every emotion we can produce is probably healthy in doses and anger is certainly one of them. Things happen in life and processing, as well as expressing, anger can be cathartic. It might allow you to let it go, even. Rage, in some circumstances, is probably necessary, too. But, rage is for the really big things and it isn't meant to be set off everyday. Identifying how to manage your anger well and keep rage at bay, unless its rare time has come, is part of a developing good mental health. What else is going on with you or what true rage isn't being expressed, if you are experiencing rage on a regular basis? How can you get at letting that rage go and, maybe, it is through feel angry about something you haven't let yourself feel angry about. Of course, anger should be expressed amongst contentment, happiness, humour, joy, and many other emotions - even sadness and grief - that make us whole humans living a full life.
An interesting bit of research on how rage may be triggered (putting aside my concerns about the poor mice): http://www.medicalnewstoday.com/articles/306469.php