It drew closer, not even hesitating when the human balked; they always did that. It wasn't like It liked being hated and feared, but the emptiness inside of it was far more powerful and far more dreadful than the fear of a human. They thought they were miserable- Hah! It couldn't laugh; not like it would anyway, as the despair it felt was more than enough to make even the happiest thought run away to someplace far, far away where it would never be heard from again; the dementor wished it could be happy. The best it ever got was a few happy memories from the humans, before they chased it off again.
The wild humans were better than the ones in the farm, though. Those ones had so little joy left in them that a dementor could fight for years and not find enough happy to delay even a single pang. Just one of the consequences of living in the city, it supposed. Azkaban wasn't that horrible, it supposed; there were plenty of others to socialize with, even if they were all hopelessly depressed.
Really, the only things that ever made them feel better were those patronus things- the flood of happy was just fantastic! The dementors danced inside when the humans brought them- they just couldn't grasp why the humans didn't give them patroni all the time, even if the joy was a bit overwhelming at first.
Or chocolate; they found that chocolate was a decent substitute for happy memories. Ice cream, too. It could remember more than one occasion when it'd sat with some unaware mortal as it devoured a tub or two of ice cream, hardly missing the occasional bit it scooped out. There were several things that helped with the despair they felt constantly, but they'd found that happy memories were the best.
That is, unless the happy memories involved clowns. Dementors hated clowns.