Put the egg in your palm and try to squeeze with mighty force. It's impossible. My colleagues were trying their lucks though. :O I didn't participate. I was more interested with the theory as I'm labeled as the Googler at work. Hehee..
Here's the best answer that I found:
Because if you apply equal force to two ends of an egg it wont crack. It is physically impossible.
However...(another extended answer):
It will break when you overload pressure at one side instead of both.
I'm off to practice now.