Not unexpected, because she's always been a nice kid, but my niece (in law) who's just turned 18 is just so freaking grateful and nice all the time.
So happy with the dress we sent her for xmas, and for thinking of her, she never went through an ungrateful teen stage (I've known her since she was 12/13) and is always polite, really tries at school even though she's not academic, labours over her homework etc.
Also she's way, WAY gorgeous, so could have gone the other way easily, and just isn't, eschewed cheerleading for soccer & football, her friends are nice, she's really accepting of people with alternative lifestyles (her best friend is a lesbian); which isn't always that common in high school.
She's just really sweet, no one I knew at that age was very sweet!