First of all I wanna say don't be mistaken, do not go into this movie expecting a Christmas classic, or a fun holiday romp for the whole family, because it is not.
I think that's what a lot of people were expecting, and got disappointed when that wasn't what they found. Another thing that I think upset people was that Ben Stiller wasn't . . . funny in this movie. At least, not in the way he is in some of his older films. It's a lot more soulful and a lot less cartooney than a lot of his previous works, but I don't think that that is to the films detriment.
As an aged out foster kid from Ohio, I can truly say that I have never in my life felt so connected to a movie. When I was put into a foster home out in rural Ohio, I met people like the boys in this film. I've met foster care workers like the one portrayed wonderfully by Linda Cardellini, and I've met and have family members like Ben Stiller's character, Mike.
In an age where every movie is a spin-off, reboot, sequel, or rip-off, I am so, so glad that such a new, unique, and creative movie exists, and that it has the opportunity to portray what life can sometimes look like for kids in foster care, kids going through sudden and tragic loss, in a realistic and non-sanitized, overly positive way.
That being said, I'll be the first to admit that it's not a perfect film, because no such thing exists, and that the humor definitely won't be for everyone. But I urge you, especially if you are a foster parent, child, or social worker, to see the film. It has so much heart put into it, and if you're willing to forgive realistic, human characters, than you might just find and see some of the beauty hidden under the sex jokes and animal poop.