Eurasians/Amerasians. Only those who disrespect every other normal person in their class/grade/school. But most Eurasians/Amerasians I know IRL are like that. Sorry Hollie-chan, 'M' and 'A'.
Certain People named 'K', 'I' and 'R'. 'K's are super rude - those who act all nice and sweet just to turn against their friends at the end of the day. 'I's are the popular girls - those who brag about their achievements everywhere (including YouTube). They put the hardworking, brilliant people to shame. 'R's come up with sad, pathetic stories so everyone will pity and care for them.