In Plato's apology why does Socrates think so many people hate him?

The people hated Socrates because the core basis of his philosophy was "wisest is he who knows he does not know." Socrates literally traveled around and told people that they were ignorant and didn't properly understand what they thought they understood, and he called all beliefs into question. Socrates thought true wisdom stemmed from self knowledge, and the realization that we can't know everything.

For obvious reasons, the public only saw Socrates as, to be blunt, an a** because it seemed like all he did was tear down other people's beliefs.

Hope that helped!! I think Socrates is awesome :)