The Infamous American $20 Bill 9/11 Coincidence

I realize this is old news and most people have heard or seen it in some form or an other - If not Just Look Here.
My ol' Pal Chummy from work actually showed me the $20 foldy thing recently and it was kinda freaky, kinda weird, a coincidence - a conspiracy????....Nevertheless, I couldn't get it out of my mind, and I was asking friends and family if they had seen or heard of it and a lot said HUH? (cause we are in Canada you see, and all you can fold in money here is the Queen having crossed eyes, but I digress....)
I found the above mentioned link and I didn't realize you could fold the $50 and $100 into an uncanny 9/11 picture as well. I have lots of questions swirling around my vast mindscape concerning WTF? How does shit like this happen? What is the anatomy of a freak coincidence? Why is the world so creepy?