Why is the mood and tone generally the same?

The first difficulty in distinguishing the two is that there is not very often a clear distinction made for the terms.

By some definitions (but not everybody's)

• Tone refers to the attitude taken by the narrator. eg. He speaks in a condescending tone, he fosters an elitist tone, or she takes on a pleading tone.
• Mood refers to the attitude taken on by the characters in the work.

Most often the tone and the mood would correspond. The writer would try and have both the narrator and the character convey the same attitude. Although it is entirely possible though for them to be different.