They had elected a government after WWII that wouldn’t sell US their oil cheap, so we sponsored a little bit of a revolution and placed the Shah on the throne and we got our cheap oil for many years.
Remember the Shah of Iran*?
His people hated him for many years and didn’t particularly care for America and the Americans who live there for putting him on the throne.
That led to a problem in the 80s for Jimmy Carter which allowed Ronald Reagan to be elected, which set the stage for the Bushes, and, well, here we are.