I dropped a finished model on the floor once - right after I had photographed it, so at least I have a record of it. Parts everywhere, some of which I still haven't found. I couldn't find it in myself to be really upset about it - things happen - but I don't plan on doing it again. I just put the pieces in a box. Maybe it will get put back together one day, but more likely I'll just use parts of it for something else.
I feel like the process of building of a model is the important part - once it's finished, it's done - on to the next one.