probably because you dont care about that person/ thing anymore. forexample lets say you are best friend with someone in high school and he slaps you, you will start hating on him, but then you move on and go to college and find new friends so you kinda forget about your other friend or even if you meet the other friend you dont care too much about him because now you have new friends at college … So yah I know its a bad and childish example but you get the idea you just move on and dont care about it thats why you dont hate it anymore … am I making sense 