'Angering your opponent is a good strategy - sometimes' is the title of an article published by Discover: Science for the Curious.
Humans understand how anger in another can influence their performance,
for better or worse, and use the emotion strategically against
competitors, new research confirms.
Researchers predicted that anger would enhance performance in the
strength tests, and that participants would choose not to upset their
opponents so as not to give them an advantage. In the mental task-based
tests, however, researchers predicted that participants would try to
anger competitors, and that the emotion would impair their mental
Any activity associated with preparing a person to survive a violent encounter (e.g. martial arts, self defence, law enforcement methods, close combat, etc) needs to understand emotion and their effects.
The strategic use of emotion is a part of your plan to defeat an opponent.
Anger produces a cascade of hormones that are evolutionarily designed to promote survival. The hormones are evolutionarily designed to increase strength, speed, endurance, decrease sensitivity to pain, and to reduce the inhibition to aggress. It also results in 'tunnel vision' and reduces the search range of solutions to a problem.
So it depends on how you plan to defeat your opponent whether or not you attempt to elicit the emotion of anger in them.
Emotions are always a double-sided coin. What emotion do you want to elicit in yourself in order to defeat your opponent or at least not to be defeated by them. Anger is one such emotion that can assist or detract from your efforts.
When you study techniques and tactics, also study emotion. It is a huge part of a combative encounter.