Is it really a sin to feel anger towards someone?

Hi All,

Is it really a sin to feel anger towards someone? Until very recently, I was under the impression that one of the major differences between Judaism and Christianity, is that (aside from one single exception — the commandment against coveting) Judaism is only interested in actions, not thoughts or emotions. However, I have recently seen this video of a Rabbi warning against anger: https://www.youtube.com/watch?v=UaE6Pe9Uy98.

In fairness to the Rabbi, he could have just been giving a general health warning about anger, or warning that anger could lead to sinful actions, rather than labeling the emotion of anger itself sinful. I’m not sure.