Optimism is, from the point of view of being an appealing social partner, a pretty good thing. If positive things are likely to happen to me—or, really, if I can persuade you I think that good things will happen to me—then I'm a good bet as a friend, ally, or mate. Not only that, but the nice thing about predictions about the future is that, being about the future, they aren't wrong, at least not yet. Being strategically optimistic seems like an eminently reasonable strategy.
