What's the difference? "You are making me angry" and "Right now I feel angry because I am not getting what I want"
"You are making me angry", the focus is on blaming the other person for causing you to be anger, implying a direct cause-and-effect on you, injecting feelings of anger into you. (not at all possible unless you give them that power over you, and I bet you're doing this in other areas of your life)
"Right now I feel angry because I am not getting what I want" this statement takes a more introspective approach by acknowledging the individuals feelings and points to the real reason they are angry. This is ownership, this is taking responsibility for one's feelings by having the consciousness and willingness to be vulnerable and state what the real truth is. When doing this a person can start to see what's creating a negative experience in the moment and take action from what's within their control. Notice they are not blaming anyone. They are not complaining, this statement is matter a fact and with some curiosity it can be unpacked and explored with openness and wiliness to move through the situation easily.
By expressing emotions in a more self-aware and reflective manner, the second statement allows for a deeper understanding of one's own emotions and the underlying reasons behind them. When we live from the paradigm it's everyone else's fault for how you feel or the situation the feeling is helplessness and overwhelm because you can't access what's within your power and control and there's no solution.