Picked up a contract to haul one single ton of some mineral for an obscene amount of profit, something like $5K, in my hauler. I'm already loaded up with other various cargo to make the run even more profitable.
But now I've overloaded my ship and don't have the range to make the trip anymore, so I sell off the excess to get a range boost and launch, realizing right after I detach that I've sold everything ... including the single ton for which I was making the trip in the first place.
Then there was the time coming into dock. Just dropped out of SC and had lined up on the station and was waiting to get into range so I figured it was a good time to hop inside the options menu to make some adjustments to the key bindings. After a while all sorts of craziness is happening in the background. I have an extreme closeup of Beagle 2 station and my beautiful ship is pinballing all around the crevasses along its side. I exit the menus just in time to see the explosion.
I'm convinced that as the game evolves I will discover new and improved ways to perfect stupidity.