Some people aren't interested in getting to a solution or finding a way to get along - they say, "Just let me be mad!" Is that okay? Not if they are not willing to slow down and talk to help resolve whatever is the issue. But, you also want them to express those feelings whether valid or not.

Feelings are bad or good; they are just indicators. Therefore, they respond to the stimuli they receive and are untrustworthy and fickle. You can reinforce the idea that feelings are primarily responders and often untrustworthy by considering two simple statements:

Bad can feel good
Good can feel bad

“Bad can feel good” is easy to prove. You have no doubt experienced feeling good, even excited, as you encounter temptation and sin. But it is followed by an inner conviction that you have done something wrong. That good feeling about doing something bad will always be temporary unless your heart is hardened.

Vengeance is one “bad” that may feel good longer than other sins because your mind is focused on justice and “getting even.” Most other sins register quickly with regret or guilt replacing whatever positive emotion was there.  The story of any sin fits the “bad can feel good” statement and is clearly illustrated in the original sin in the Garden of Eden.
So when the woman saw that the tree was good for food, that it was pleasant to the eyes, and a tree desirable to make one wise, she took of its fruit and ate. She also gave to her husband with her, and he ate. Then the eyes of both of them were opened, and they knew that they were naked; and they sewed fig leaves together and made themselves coverings.
And they heard the sound of the LORD God walking in the garden in the cool of the day, and Adam and his wife hid themselves from the presence of the LORD God among the trees of the garden. – Genesis 3:6–8 (NKJV)
Put yourself in Eve’s place and let your emotions follow the story. Eve was swept away by the appeal of the fruit – good for food, pleasant to the eyes, could make her wise – so she ate. It sounds like she felt good about eating the fruit, BUT it was bad.

And to prove it was bad, notice where their feelings go next. “Their eyes were opened…knew they were naked…hid themselves…” Feelings were responding to the reality of what God said would happen.

Most often, the good feelings happen before and during the sin because we do not listen to the conviction of our conscience or the Holy Spirit saying – “Think about this! Don’t do it!”

“Good can feel bad” is also real. Consider the emotional conflict you experience when you know a close friend or relative is sinning. You know it is time to speak with them, so you gather your courage to do it, but your emotions work against you. And, in those cases where the conversation goes poorly, you may experience feelings of regret instead of peace or joy for doing what was right.

A good parent disciplining their child understands that “good can feel bad.” Similarly, when a good leader shares the truth with a person because they are not doing a good job, it often does not feel good.

Consider the following:
Just because I do right, does not mean I will feel right (at that time)
Corollary: Just because I feel right does not mean I am doing right