Feelings are like the weather. One can talk all they want about whether it should be this cold or that it shouldn't be raining. It doesn't change the weather. One can similarly think that "I shouldn't be angry or I shouldn't be crying." And similarly it does not change the way we feel.
Acceptance of our feelings allows them to flow and lets us use our energy to choose how we wish to think or act in response to our feelings. Thoughts have an element of control like setting the sails of a sailboat to catch the wind. Trying to control our feelings is like trying to control the wind.