>>724749000
It makes sense if you go The Girl route with Kris and realize why she has always been living in Asriel's shadow.
Her only childhood friends were Dess and Noelle. Noelle being someone who isn't very forward with her friendship with Kris.
Dess being someone who always gave Asriel more attention
Then there's Kris herself being given boy clothes, forced to grow up with no friends except the overtly happy girl who seems avoidant, add this to Noelle almost denying being anything other than neighbor-friends all her life and you get the recipe for a misanthropic girlfailure who wishes she were anyone else. Especially wishes she were her cooler older brother who got all the attention.