I think the Sims 3 babies are annoying in general. The fact that their overly needy, (I don't think real life babies are that needy), the fact that their left on the floor like a toy baby, and you could snuggle and manhandle the baby till the cows come home, and their social needs go down as soon as you leave the room. I don't like the babies at all. I actually feel bad for the Sims 3 Babies. They're treated like cats and small dogs in Sims 2: Inappropriately manhandled.
I never understood this. I was always annoyed with the tiniest things, and find them unrealistic, yet the big too realistic things annoy me in the game.