My dad gets it into his head that carers won't let him do things, eg that they tell him to go back to bed if he wants to walk around (one may have done once in particular circumstances but then he thinks they're going to tell him off every time). So the manager has printed and laminated a sheet for him which says "Manager says that you, Dint's Dad, can walk around whenever you want to. It's important for you to walk because... Manager says that you can xxx ... it's important that you do because ..."
He's shown it to every carer he's met since and made sure that they've read it 
He used to refuse to have a shower because he was worried about them handling him awkwardly and hurting his back. But the manager has helped him draw up a "contract" about how he is to be helped with a shower, and he is now happily having a shower, with the carers signing the contract each time before they start to help him.
There's lots of other examples of this sort of thing, and it makes him a lot happier.
Do other care homes do this sort of thing? I think it's pretty great, but I may just have low expectations.