Iran actually had the last laugh not too long ago.
Kuwait was the chief financier of Iraq during the Iran-Iraq war (1980 to 1988), and Iraq owed a lot money to Kuwait.
Iraq/Saddam was supported (including militarily) by the US and Russia, until Iraq had a pissing match with Kuwait and decided to invade Kuwait over that in 8/1990.
Saddam did request "permission" (via our US State Dept official, 3 times; there are videos showing the meetings with our State Dept official in news archives) to invade Kuwait. When the US (under George Bush Sr) did not reply, Saddam thought no reply was an OK and began his invasion.
There's also a video of Donald Rumsfeld shaking hands with Saddam during a meeting, in happier times, in the archives.
The rest as they say is history.
Iran (Shia Muslims) must have been pretty pleased that their enemies Iraq and Kuwait (both Sunni Muslims) fought with each other, and Iraq got decimated later by the USA in the ensuing war. Some might even go so far as to say that divine providence was on their side, to have their enemies fall without too much direct effort from them. Just sayin.
Watch to documentary "Severe Clear" (2010) to see how we
were [mis]led to believe that Iraq had something to do with our 9/11/2001 incident, to justify our military involvement there to our people. The USA can't distinguish one group/faction of Muslims from another.