From my bipolar point of view, it's okay to get angry and have emotions. I think it's okay to express them. "Normal" people express anger all of the time.

What's not okay is what I do when in a rage. I break stuff and physically attack people. Hitting someone is never okay. So, if you only spewed out a few nasty words and didn't put your hand on him, I'd say you're doing better than a lot of others. If you ended up punching him, then yeah, you went too far. You were wrong.

But please take my opinion with a grain of salt. I have psychotic episodes, so my opinion may not be the best one.