Remember, anger is a choice - a negative emotion allowed to run amok in one’s mind. Nobody actually “makes” another person angry. Anger arises in oneself. Anger can even be directed towards oneself. For example, if an activity undertaken does not yield the desired outcome, one might be disappointed and disgruntled at one’s own performance.
Whether anger is directed at another or at oneself, it is the same mechanism at work. An unwholesome thought arises in the mind - such as self-criticism because something didn’t happen the way one wanted - and that unwholesome thought is then perpetuated and clung to. Before long the person becomes angry, perhaps even to the point of losing self-control, because he is not able to get what he wants.
If one has not learned how to check and discipline the mind, then one may say wrong things at the wrong time or say something nasty or otherwise act inappropriately towards someone else. Later, one feels guilty and regrets behaving in that way. This causes one to get even more upset with oneself.
But nobody else makes one angry. One makes oneself angry.
This reflection by Luang Por Plien is from the booklet, The Abandoning of Anger, (pdf) p. 5.