Okay, like two/thirds of this post are just fucking brain-dead. (Not an American btw.)
Afghanistan and Gulf War were the most straightforward of all conflicts US has been involved in in the 21st century.
Afghanistan - that's where the Taliban were, and the Taliban did 9/11 (kinda, Al Qaeda did, but they had ties, and bin Laden was there for a time). The only problem was that the US didn't consider the regional politics and allied with Pakistan, which was funding the Taliban, since stable Afghanistan was bad for Pakistan.
Gulf War - he, y'know, INVADED KUWAIT! What the fuck is so difficult to understand about "Invading sovereign states is bad actually"!?
Iraq War was bad though 100%
Yes.