It's alright once they get older - but in the early years adopted kids are invariably violent and impossible to socialise because of whatever traumas they suffered under their biological parents.
I mean, my kids are being brought up in the leafy middle class environs of Hampstead with two blissfully happy and successful parents, and every single day I amaze myself that I've not killed at least one of them. So I can only imagine what it's like to have to care for a truly dysfunctional child who doesn't even share my DNA.
I know a couple with adopted kids. I've tried to chat to the boy, aged around 7, and literally all he does is hiss at me. I basically don't bother any more.