Albert Einstein is credited with saying "If something has several explanations, the simplist one is most likely the true one."
In my opinion these are the simplist explanations.
Aghanistan started because of 9/11. You have to remember that Americans are not used to war taking place on American soil. We were lolled into a false sense of security and never expected that American soil was vulnerable. the reaction was based on fear and disbelief. True it was the wrong conclusion, but that was the reason. Sorry, no conspiracy, no attempt to control foreign oil sources.
The simplist explanation of Iraq was rumors stating that Iraq had WMD and was planning to use them against the USA. this was aggrevated with Saddam's boasts during the first Gulf war when he bragged that he had wepons that would bring the western world to it's knees. The simple fact is we believed Saddam and feared him.