The other day my wife Kat commented on a newsletter I'd written where I explained how you could use "negative" emotions in your magical work. She asked me if that was really a good idea, especially since I'd essentially be integrating those emotions into the magical working. It was a good question to ask, but what it highlighted to me is just how much cultural baggage we have around the word negative as well as specific emotions. I explained my reasoning by noting that I don't think any emotion is inherently positive or negative, but that if we believe an emotion is negative or positive it is because of the cultural associations that have been placed on that emotion. The problem with that association is that it causes us to not genuinely experience the emotion.
Anger, in and of itself, is not inherently negative. The expression of anger can be negative or positive, depending on what a person does, but that expression doesn't make the anger wrong or bad or negative. The expression isn't the anger in and of itself, but if we examine anger from a cultural perspective what we tend to find are associations of negativity with anger. The same is true with fear, sadness, anxiety, or any other emotion that is "negative" On the flipside love and happiness are considered "positive" emotions. However expressions of love and happiness can be negative just as expressions of anger, sadness, and fear can be positive. There is nothing inherently polarized about our emotions other than what we choose to believe about them.
Putting anger into a magical working could be quite useful depending on how you are using anger. I have used anger to fuel some of my magical work, with the goal being to improve a situation. I felt the anger and instead of allowing it to fester I chose to direct it into the magical working because I felt that it would give me an outlet that was healthy, while producing a result that would improve the situation. I've done the same with other so-called negative emotions and have found each time that I have felt empowered because I've actually given myself permission to integrate those emotions into the magical work. By providing an outlet that allows me to express them as a positive force of change in my life, I am able to be present with my emotions and allow myself to find resolution about what I am feeling.