To be honest, I love watching animals have their own mindset and intelligence. I mean this is Sims. Sims is supposed to have some sort of unrealistic element that's left up to the player's imagination. It has since day one. If the game was completely realistic, it would simply be boring.
What really annoys me is with the Daycare profession, a parent drops their kid off, the daycare man/lady (depending on your Sim's gender), tries to pick the kid up, but the kid is stuck unable to join the rest of the clan in daycare.