As an actor, demonstrating your feelings in front of people is not what you're supposed to be doing. You're supposed to hold your emotions and control them, and not show them all over the place.
James Hong[While voicing] you have to create a feeling for what happened before a scene, what's going to happen after a scene, and what you are doing in a scene. You need to use your imagination even more and once your emotions are up, then your voice and expressions will go accordingly.
James Hong