The kids were unbearable

At first, the son is a realistic. Sure he's really smart and asks more philosophical questions than most other kids, but he still has realistic emotions like fear, curiosity, sadness, etc. By the end of the film, however, he and the girl are both robotic angelic saints with zero emotion. I'd be crying if I were a kid and had to leave my family behind to live in a new world, never to see them again, not like "it's time for me to go, dad, they've chosen us to start over" with a cold dead unexpressive face. He admittedly gets a little choked up at the end when he leaves his dad, but it quickly goes away as he "understands his duty" and is running in an alien field with no society just moments later, like what 10 year old would act that way?

The little girl is even worse because she's a robotic saint the entire film. She just watches her mom die in a horrific road collision and then turns around in her seat like nothing happened. And the way she calls them "the whisper people" is so cringeworthy. The funniest part was when the UFO lands and the kids are completely unfazed at it as if they've seen one of those everyday.

It's also stupid how these kids are 100% cool with having tall creepy strangers in suits follow them around. The son is reasonably terrified at first, but again, he becomes emotionless and flat in the 2nd half and is totally fine with listening and even riding in a car with these stalking strangers.