In a radio episode on KERA Think, Harvard Medical School psychologist Susan David shared a little insight about emotions. She said that emotions provide "data, not direction."
The point being, in part, that humans have evolved overtime with emotions that give us feedback on something going on inside of us. So if we are feeling angry, then it is our own bodies that are giving us data for us to use for self reflection.
For instance, if you are angry that someone cut you off while driving you have the option to receive that anger as data or as direction. If you are a anger=direction sort of person then you may end up driving fast in order to tailgate the one who cut you off, or you may redirect your anger toward to dog at home and kick him for barking.
However, if you are a anger=data sort of person you may feel that anger and reflect on the reality that you are a person who does not like being disrespected of and you feel angry because someone's actions were disrespectful. This data may then lead you to consider if you want to keep getting angry at every slight or if you would like to do some soul work on dealing with why respect is so important to you.
To live with the understanding that emotions provide data, not direction is to live more in line with the spiritual life. To put it another way, it is important to know who you before you know what to do.