What is the matter with the pessimist?
I think it can be stated by saying that he is the cosmic anti-patriot.

And what is the matter with the anti-patriot?
I think it can be stated, without undue bitterness, by saying that he is the candid friend.

And what is the matter with the candid friend?
There we strike the rock of real life and immutable human nature.
I venture to say that what is bad in the candid friend is simply that he is not candid.

He is keeping something back--his own gloomy pleasure in saying unpleasant things.

He has a secret desire to hurt, not merely to help.