Earlier quoted context omitted.
What about the London 2012 Olympics logo? That can't be undone, and it can't be unseen once you see it (ie. the Fedex logo effect not in a good way).
The London 2012 logo was a pile pants :) Fortunately, once the games kicked off people forgot about the logo and it was a very successful event by all accounts and there was a huge buzz in the air with everyone (I'm a Londoner). Still can't believe they paid that much money for that !
If you read vertically, turn some letters sideways, and apply liberal amounts of imagination, it looks like "Zion" which was enough to offend the Iranians.