Saddam Hussein had recently come out of a war with Iran that was disastrous, especially considering that he was winning it in the beginning. He seemed to have this idea that military expansion was the way to make a nation great and strong, so he picked on Kuwait. He claimed that he was retaking it as a former province of Iraq (not sure if this is even true), and figured no one would do anything about it. He probably wanted the oil fields as well as more access to the sea, for trading purposes. He probably figured he could do the job quickly before anyone could do much about it. This last part indicates to me that the man is a complete idiot. A rich oil-producing nation like Kuwait is going to get noticed by the entire world, which depends on petroleum for its very existence. The fact that S.H. didn't see this coming suggests he has no clue about the international diplomatic sphere. He probably figured if the West backed him up on Iran (it was the bigger threat at the time), they'd back him up elsewhere.