Unnecessary voiceover

Have you ever watched a drama where during a perfectly good scene a voiceover suddenly comes on to explain what is happening in the scene or, even worse, what characters are thinking?

That kind of voiceover takes away the experience. It shows a lack of confidence in one's ability to tell a story, as well as a lack of trust in the ability of everyone involved to tell the story. It's not too different to, for example, micromanagement.

Be confident about your story, and trust those who enrolled to tell your story.