What's the most significant government deception you are personally aware of?

I thought I would start a thread looking for personal stories of government deception. This is to separate these from the well-worn theories (9/11, the moon landing, etc.) that are often debated on here. Most of these debates are based on analysis and non-personal experience. That does not make the arguments any less vaid, but I am interested in cases where a person is directly connected to an event or in direct contact with someone who was directly connected (the Haskell thread made me think of this).

My personal contribution...

It involves the first Gulf War. As you may remember, Saddam was lobbing a bunch of Scuds at Israel and U.S forces stationed in Saudi and Kuwait. You may recall this event:

Twenty-eight members of the Pennsylvania National Guard were killed when one struck a United States Army barracks in Dhahran, Saudi Arabia. [link to en.wikipedia.org]

At the time, I remember the media and the government saying it was an incredibly (un)lucky hit, since the scud is unguided. At the time, I accepted that explanation, but years later I happened to have a work assignment that involved this elderly gentleman who had recently retired after several decades at the Defense Department. Over drinks one evening, he got a bit chatty and started telling stories from the Gulf War. All of them were eye-opening as they involved operational details I had never heard anything about in the media, including gruesome details of just how easily and efficiently the U.S. military killed of thousands of Iraqi troops, but his story about the scud was truly shocking. He said the scud was intercepted by a Patriot missile fired by a battery near the barracks, but the Patriot did not intercept cleanly and rather than destroying the scud, it basically stopped it cold and destroyed the tail of the missile, leaving the warhead intact. The warhead fell basically directly down from the sky and landed on the barracks. "Warhead" and "tail" are probably not the correct terms, but point is that the scud would have landed someplace else. The only reason it hit the barracks was because of the Patriot. That this was never revealed publicly is, in retrospect, not surprising, but that evening was the first time I became aware of how easily the government lies to its people.

Anyway, that's the story. Here's hoping this thread will attract more.