There's been a lot of propaganda portraying Iran as a nation full of irrational extremists who would rather the world die in nuclear fire than live next to Israel, but that is not based in reality. Israel has nuclear weapons, and is very nervous about having a close neighbor with the same level of power. Iran is understandably nervous about not having nuclear weapons while Israel has them. Proliferation is a bitch.
Of course it doesn't help that Palestinians, the original Muslim inhabitants, are treated as sub-humans by Zionist Jews so there's very bitter hatred between the two groups.