I thought Adam was weird before...

To me, it was the parents who were creepy right from the get-go. The first ten minutes were so ridiculously over the top in terms of trying to establish just how tight-knit the family was. Actually, it was over the top in establishing the family as practically perfect in every way. Dad's this altruistic teacher, I mean "educator", who touches the souls of his students, even those wayward ones who assault him with a knife. Mom's this playful scamp who loves nothing more than giggling while throwing things at 5 year olds. Dad's conflicted about taking a job at a more modern school, where he'd be safer and paid twice as much, because, gosh darn it, he's just so committed to the waifs of the inner city. At the birthday party they throw for their 8 year old son -- in their wonderfully bohemian apartment -- they have a perfectly diverse circle of friends. And don't you know they tease each other mercilessly while son blows out the candles on his cake. But then, after everyone goes home, the treacle factor actually goes up! Mom and Dad go to Adam's bedroom and practically assault him with parental love -- cake, the dinosaur, the "best birthday gift ever!", and non-stop hugging.

The thing is that any parent watching a movie like this, no matter how dreadful it actually is, can sympathize with one thing: the loss of a child. You don't have to sell it in this heavy-handed way. What DeNiro proposed to them would, at some level, be tempting to any parent hurting that badly. They didn't need to establish them as the Greatest. Family. Ever. for that part of the plot to work.