Only child syndrome

I nanny for a 7 year old and she is a diva! I adore her and her family, but she suffers from what I call the "only child syndrome"; a bad case of it too.

She ignores me half of the time, she's only nice to me when I buy her something and hates when I touch any of her toys, artwork (I'll tell her how good she did and she rolls her eyes) or anything she owns I cannot touch or else she becomes agitated, even a pencil of hers she make a annoyed noise because it's hers not mine.

I've seen her treat her parents like this and they usually tell her to not act like that but she doesn't care. I take it personal and my feelings are guineley hurt because I'm so nice to her and surprise her with random activities like the zoo, aquarium, the park and adventures to the museum!