TONE
I feel that tone is very useful in writing for authors. Based on the author's tone we can somewhat see into the feelings that the author may have. Tone gives you  their attitude their feelings, their beliefs in an almost subliminal way. I, honestly, tend to just ignore it never focusing to much on it unless it is a direction given specifically toward looking at it, but I still do feel it and just go through the story subconsciously knowing. Without tone scattered throughout the story the tale would be monotone and bland dettering many readers from it.