Are depressed people more realistic?

[junkyardboy]

so your optimism is based on your immediate circumstances
not a very sound foundation for optimism

Isn't it the only valid foundation for optimism? The homeless guy who is sitting on a street corner may be feeling quite pessimistic, even if the headlines on a nearby newspaper say that the economy is booming. Our mood can be lifted and dropped most easily by those around us and by our particular circumstances.

granted, but not a very firm foundation except for immediate optimism
says nothing toward the future