I went to an engineering school, and one of the stories the old boys told was that at some point the city had built a new bridge, and tendered the destruction of the old bridge, and we'd put in the winning bid.

The scheduled day came, but only an hour or two after the scheduled time an urgent messenger came from the city: the neighbours were complaining, could they please just destroy the bridge all at once with the next explosion?

It turns out the civil engineers had been enjoying themselves in the interval, checking their modelling by seeing how many parts of the bridge they could blow off of it, while leaving the majority of the structure still standing...