As a social worker in a school setting, I see a lot of things.  The one thing I do see the most, though, is common 'anger.'  I am going to work on this problem of 'anger' with a third grader today.  I use the anger management program from Missouri Comprehensive Guidance Programs curriculum.  The program offers a wide range of activities and talks about 'taking care of your mad in healthy and safe ways'.  Cool that it is bringing some fun but also using casual language for a sometimes difficult subject.
I tend to do the lesson with an art technique as well, showing 'mixed up feelings'.  Our mad and sad sometimes get mixed up together.  I have done this with marbles/cardboard box or even with a spin art machine.  After rolling the marble in the box through two different colors of paint, the discussion turns to how this demonstrates our feelings becoming mixed up.  At the beginning of the art lesson, I discuss how the different colors of paint represent different feelings the child may have.  When the mad and sad feelings are mixed up, sometimes it is difficult to relay how you feel.  Your feeling of 'mad' might actually be more 'sad'.  This is a fun way to show how difficult it can be to accurately tell how we feel.  It is important in the end to identify the feelings and triggers to our anger.