can anyone tell me why Dobey hates the family(Malfoys) that he serves?

Dobby was treated badly 의해 the Malfoys so he was 더 많이 likely to disagree with their values and be against them and their beliefs. On the other hand, Kreacher was treated well 의해 the Blacks, especially 의해 Regulus.

Well Dobby is always getting hit 의해 Lucius and his cane. They always mistreated Dobby.
While Kreacher loved his family and Sirius's mother a whole lot he looked up to her. But the weird thing about him is that he wants his head up in a row with his mother 또는 something but he liked his life.