Perhaps because the origins of a certain kind of love lie in an impulse to escape ourselves and out weaknesses by an alliance with the beautiful and noble. But if the loved ones love us back, we are forced to return to ourselves, and are hence reminded of the things that had driven us into love in the first place. Perhaps it was not love we wanted after all, perhaps it was simply someone in whom to believe, but how can we continue to believe the the beloved now that they believe in us?
If optimism is important, it's because many outcomes are determined by how much of it we bring to the task. It is an important ingredient of success. This flies in the face of the elite view that talent is the primary requirement of a good life, but in many cases the difference between success and failure is determined by nothing more than our sense of what is possible and the energy we can muster to convince others of our due. We might be doomed not by a lack of skill, but by an absence of hope!
Objectively good spaces to work rarely end up being so; in their faultlessness, quiet and well-equipped studios have a habit of rendering the fear of failure overwhelming. Original thoughts are like shy animals. We sometimes have to look the other way - towards a busy street or terminal - before they run out of their burrows.
Rather than employing it as a supplement to active, conscious seeing, they used the medium as a substitute, paying less attention to the world than they had done previously, taking it on faith that photography automatically assured them possession of it.
The universe is large and we are tiny, without the need for further religious superstructure. One can have so-called spiritual moments without belief in the spirit.
He did not mean to depress us, rather to free us from expectations which inspire bitterness. It is consoling, when love has let us down, to hear that happiness was never part of the plan.