An optimist will tell you the glass is half-full; the pessimist, half-empty; and the engineer will tell you the glass is twice the size it needs to be.
A pessimist is somebody who complains about the noise when opportunity knocks.
The reason we all like to think so well of others is that we are all afraid for ourselves. The basis of optimism is sheer terror.
If you pretend to be good, the world takes you very seriously. If you pretend to be bad, it doesn't. Such is the astounding stupidity of optimism.
The optimist sees the donut, the pessimist sees the hole.