It's important to note that "-er" is not a suffix that directly indicates anger. It's a common suffix that typically forms nouns denoting the person or thing that performs an action. In the case of "anger," it's the person who feels anger.
Here are some other words with the "-er" suffix:
* Teacher: One who teaches.
* Writer: One who writes.
* Player: One who plays.
So, while "anger" doesn't have a suffix directly related to the emotion of anger, the "-er" suffix adds to its meaning by indicating the person experiencing the emotion.