Suppose there is a lake between the tee and the hole, too big for the golfer to hit the ball all the way across. Should he envision/anticipate a hole in one, and waste his first stroke hitting the ball into the water, or should he acknowledge that this hole will take multiple strokes, and hit the ball around the lake?

Whatever will produce the better result.

Remember that the instrumental litany I proposed is, "If believing X will get me Y and I wish Y, then I wish to believe X." If believing I'll get a hole in one won't get me a good golf score, and I want to get a good score, then I wouldn't want to believe it.