I've yet to lose/break a piece, this can be attributed to the fact that I just bought my first one a week ago. I have witnessed the breaking/losing of some awesome pieces.

Leonidas- My buddy had his unnamed yellow bowl on his desk, and shifted his keyboard on accident. This caused the bowl to fall, hit a subwoofer under the desk, then fall down the heating grate in his wall. We sat there for like a minute then somebody just went "WHAT THE FUCK!?" We tied a camera phone and a maglite together and dropped them down to see if the bowl was still in one piece. It is, but the only way to save it would be to cut a hole in the vent...which we plan on doing. We named it Leonidas after it survived the 15ft fall.

Another friend of mine was smoking out his bedroom window with his brother. They would pass the bowl between their bedroom windows. One of them dropped it, breaking it into thousands of pieces.