Why do people hate on people?

We all know Chicharito is one of the best strikers in the world but some people still say he is overrated. Also some fools as Giovani is done, he is only 22 he has plenty of time left. He has as much potential as Ronaldinho. The hate their getting is irrational. Just like idiots who hate George W Bush. Bush is one of the best presidents ever. He gave the largest amnesty bill ever. He approved of tax payer paid Chicano schools thru out the country. He advocated and signed a program that helped undocumented works to buy houses and receive bank accounts. Obama on the other hand has deported more immigrants than anyother president in history. He might reach the 3million mark when he is done. So far 800,000.