Ephesians 4:26-27 - Anger!?

Ephesians 4:26-27  /  Anger!?

In the larger passage of Ephesians 4:25-32, this instruction is easily Paul's most controversial.  It does not contain an obvious counterpart or balance of the others.  Is Paul commanding anger? "Be angry and do not sin"   
Or is Paul only intending to acknowledge anger as part of the human experience, and following that up with warnings/cautions?  "In your anger do not sin"