Because you hate me. That sounds like a snide answer, but you deliberately do a lot of things to hurt me and I just can't stand having you around.
But, if we forget about me and talk about the guy behind you on the bus, he hates you because (take your choice) he is racist, he thinks you don't believe in God, he thinks you are pro-choice, he thinks you are gay, he thinks you are Muslim, he thinks you are the reason he lost his job, or it is one of the hundreds of reasons that some people use as an excuse to hate other people.
I don't. The thing is people choose to believe what they want. FOR EXAMPLE why ask if you if you already know the answer.
I don't hate you, your name indicated you were Kool.
I dont and I wont, becoz hating sumone makes sumthng bad grows in ourselves too, n I dnt want tht.
I generally do not give people I don't appreciate enough attention to actively hate anyone.