He was a complete moron who had the balls to talk down to any superior that tried to tell him he was a complete moron, and most generally win that argument. Most superiors would promote him and recommend him for positions just so they could get rid of him.
He lied, cheated and stole many of his awards. He gave himself the first Purple Heart saying he was wounded 20 years prior in WWI even though there were no records. He gave himself Flying Crosses and Air Medals for single cargo flights to non-hostile areas when you are required to have combat sorties and lots of them. He was so up to his neck in bribes and debauchery that he made what many consider the greatest act of military ineptitude ever and then recommended himself (and received) the Medal of Honor for it.
Japan could have been taken much sooner and possibly without nukes, but he forced the military to retake the Philippines first, to make himself look good, then had to restage the landing so it could be filmed.
He lost thousands of troops in Korea after he was told there were over 200k Chinese troops there not to go any further, but he did anyway. The only way he got out was to use illegal gas against them.
Yeah... not a fan.