I think we’d like life to be a train. And you get on and pick a destination and get off. And it turns out to be a sailboat. And everyday, you have to see where the wind is and check the currents and see if there’s anybody else on the boat you can help out. But it is a sailboat ride. And the weather changes, and the currents change, and the wind changes. It’s not a train ride. That’s the hardest thing I’ve had to accept in my life. I just thought I had to pick the right train.

Barbara Brown Taylor (b. 1951) American minister, academic, author

Super Soul Sunday, s. 5, ep. 522, “Why Life Is Like a Sailboat Ride,” Oprah Winfrey Network (9 Nov 2014)
    (Source)

Starts at 0:48 in the source video. Usually just rendered down as "I think we'd like life to be a train ... but it turns out to be a sailboat."