But it is important to maintain some moderation and rein them in. Emotions are powerful, and if you don't learn to exercise some degree of control them, then they will control you.
I think it helps to understand that emotions have a purpose. For example, fear helps you avoid threats, and anger pushes you toward taking action that is needed to change a situation. If they're serving their purpose constructively, that's good.
But if they're not, they need to be controlled. For example, when fear makes you avoid something which is actually safe, or when anger makes you act in a rash manner or suffer mentally over things you cannot change.