TheEnglishMaster:
I don't know what neuroscience has to say about the vanity of authors, but, believe me, it cannot be underestimated! Writing can be a lonely business, so ANY comment, however unoriginal, slakes that craven thirst and encourages us to keep at it. Don't starve the geese who lay the rosy-cheeked eggs.
I'm not sure I enjoy having my likeness to a goose being pointed out that explicitly, but otherwise I can only say amen: Authors are vain people and they thrive on feedback! Personally, I enjoy all comments. When a story is new, I am curious to see how others view it, and when a story is old, I am happy to see that it is still being read and appreciated. That several commenters point out the same feature, is actually quite helpful as it tells me that I have really succeeded with something (or totally blown it). I especially enjoy comments that discuss the characters as if they were real people. If you do it, all professors of literature will tell you that you are hopelessly naive, and all authors will love you! Don't be shy, give us what we want: More comments!