One of the re-runs the other night included the story where Jerry trys to ruin a trade of items between Newman and Kramer, by warning Kramer that Newman's item is no good.
This seems to me to be one of the few times that Jerry has screwed Newman, compared to Newman and the fleas in Jerry's apt., etc., that make Jerry antagonistic toward Newman.
Any further references/thoughts as to why Newman dislikes Jerry, beyond his general neatness???