What is the worst possible PR mistake a company can make?

Inspired by the KBlimp debacle, I'd like to know what is the worst that a company can do and still survive. For those who don't know, a Goodyear blimp was flying over the Republican National Convention, and someone logged into the live stream chat and responded to a "God bless the USA" comment by saying "Fuck the USA". This caused a huge shitstorm, and the live stream was quickly taken off the air and the person responsible was fired.<br><br>So, what is the absolute worst thing PR can do and still survive?<br><br>This was inspired by KBlimp. If you are a republican, please do not take this as an attack on you, it's just that the event was a really big fuck up that I PR can't recover from. I am completely apolitical as well.