Let me tell you a secret:
"kind" and "angry" aren't antonyms. One doesn't exclude the other.
A lot of folks these days will tell you otherwise. If they can be kind and angry, they open themselves up to an idea that terrifies them: "responsibility".
It's important for you to hold, in your heart and in your head, that "kindness" is a quality, and "anger" is a reaction.
If you're truly a kind person, avoiding anger should be damn near impossible.