If Someone Is Called An Ugly Duckling, Is It An Insult Or A Compliment?

If you're still growing up, it's an insult; if you're an adult, probably a compliment. In Hans Christian Andersen's story, a mother duck was puzzled by one of her brood of ducklings. In the first place, this one egg took much longer to hatch; in the second place the "duckling" looked very odd – large and brown, not small, fluffy and yellow. On the other hand he was an excellent swimmer.
As time passed, the ugly duckling was more and more ill-treated by the other birds; when even his mother got tired of him, he flew away. He spent a miserable winter looking for a home and friendship, where his ugliness wouldn't matter. Finally he could bear it no longer. He had seen some wonderfully beautiful white birds swimming by, with long graceful necks; he decided to go to them. They would surely kill him, but that would be better than his present life. So he went to the white birds, bowed his head waiting for their deadly pecks – and saw, reflected in the water, a white bird even lovelier than the others. The ugly duckling was now a swan.

Probably an insult