After I raged: my own stupidity. It didn't work every time, but smiling at myself (no forced laughing, I'm not the Joker) brought me down to Earth again (reduced stress rather quickly) in the past and helped not getting bullied by my worst critic - me. You may not feel like it when you are angry and it will probably feel strange at first. But smiling (even without the corresponding emotions) can trick your brain that releases dopamine, endorphins and serotonin then, giving you a better mood.
I can't quarantee that it will work in every situation. Just try it, you have nothing to lose (aside from a grumpy face).