Why don't people like kylie jenner?

so i was looking at their youtube videos, and alot of comments say they LOVE kendall.. ik she does most of the modelling and stuff but also comments say that kylie is a little brat. i don't understand why? they both seem so sweet! don't get me wrong im no hater, i was just wondering. i actually love their show! and them, jenners & kardashians<333