Purveyors of inspirational stationery supplies love the Emily Dickinson line "dwell in possibility," and it's easy to see why--it's basically permission to daydream. But have you ever come to a crossroads in your life at which essentially anything is possible and you find yourself dwelling in possibilities like, "What if I don't get a job?," or "What if I never find a place to belong?" Classic times for this sort of dwelling-in-negative-possibility include after college/grad school or the aftermath of a break-up. School or the relationship were "life anchors" of sorts, giving you a fixed constant, and, when that stability is gone, it is both exhilarating and terrifying.
Of course, those life anchors just gave us the illusion that we're settled on a defined path. Life is such that anything is possible at any time, both good and bad; it's just more obvious during the times when you feel like your life is a giant pile of loose ends. There's nothing stopping me or you from going down the road of anxiety and worry during these pivotal life moments, but, if you read the poem from which the line is taken, it seems to me that Dickinson was writing from a place of both positivity and possibility.
Anchor-less is not the same as rudder-less. We can always set a course for great things. Maybe we don't always have control over where our metaphorical ships come in, but we can chose to imagine wonderful things, and live our lives in ways that increase our odds of having them. (And we can learn to be our own anchor, but that is a topic for another day.) Dwell in possibility, but not without positivity.