In the New York Review of Books, the late poet Mark Strand ruminates on a great exhibit of Hopper's career, focusing on his remarkably graceful drawings, and the sadness that comes off his work:
Recent major exhibitions in London, Paris, Rome, and Madrid testify to the universality of [Hopper's] appeal. It couldn’t be just the way New York looked in the first half of the twentieth century or the dated look of hotel rooms, of people in offices, staring blankly or dreamily into space, that accounts for such interest.
Something lifts the paintings beyond the representational registers of realism into the suggestive, quasi-mystical realm of meditation. Moments of the real world, the one we all experience, seem mysteriously taken out of time. The way the world glimpsed in passing from a train, say, or a car, will reveal a piece of a narrative whose completion we may or may not attempt, but whose suggestiveness will move us, making us conscious of the fragmentary, even fugitive nature of our own lives.
This may account for the emotional weight that so many Hopper paintings possess. And why we lapse lazily into triteness when trying to explain their particular power. Again and again, words like “loneliness” or “alienation” are used to describe the emotional character of his paintings.
The answer, sez me, may be simpler: we see in his images his struggle to live in his work.
The fact is, being alone is central to the work of any artist striving for personal expression. Call it loneliness, call it individuation. Call it what you want, the fact remains: you can't find yourself trying to please someone else.