I blame Ace refers to a ChromeHounds (XBox360) squad leader who's gamertag is FullMetal Ace. Whenever something would go wrong during a mission, whether it was bad luck or someone shooting a teammate in the back, the offender would shout "I blame Ace." As time has gone by, this has moved form being reserved to a gaming platform to being used in day to day life. So any time bad luck or just bad things happen, blame Ace!
You're killed by friendly fire, the offender shouts "I blame Ace! If you girlfriend is doing your best friend, I blame Ace. If you've just been fired from your job, I blame Ace! If the midget show has been cancelled at the strip club, I blame Ace!