It will do you no good to get angry at her being mad. Figure out a way to empathize with her and figure out what’s upsetting her. The last thing you want to do is get pissed at her for her feeling the way she is.
Your girlfriend wants to know you are on her team and looking to understand her point of view. She seriously wants to know you’re making a real effort to connect with her emotionally and understand her.
When a woman is happy in a relationship, it’s easier for a guy to understand her negative emotions. It’s about making the effort; you don’t have to be perfect.
When your girl gets mad, you need to give her the venue to understand her emotions and make a real effort to relate to her. This will actually make you move closer together.
You will really screw up if you ignore the fact she is upset. That will get you nowhere fast.
If your girlfriend is angry, you need to stop what you are doing and open your ears to start listening.