They think they have Israel on the ropes. Israel's military is better-equipped and better trained, plus virtually every adult in the nation has military experience. The Israeli leadership is also smarter than any of the leaders of the countries that surround it.
Iran's leader is a hateful little bastard, but most of the citizens of his nation realize it at this point. The Syrian leadership is barely hanging on and Egypt has not stablized yet from it's revolution.
Ask the vaunted IDF how they made out the last time they attacked southern Lebanon.