Noodles originally disliked him because he was getting all the attention.
His owners even threw away Noodles's favorite toy- a stuffed lion -after J.D. spit up on it, which upset Noodles very much, but he warmed up to J.D. eventually and Steven ended up saving Noodles' stuffed lion from the trash and cleaned it. Maybe J.D. will grow up into Noodles's perfect person. It's okay if a baby hears dogs talk because babies have such small brains they won't remember it.