I created an account just to vote this one up.

A memorable anecdote concerned removing a dent from a storage tank. It had been filled with a warm vapor and accidentally sealed, and when the vapor cooled it reduced in volume, resulting in predictable (but slight) denting.

The plant engineer had to stop workers from attaching high pressure pumps to the tank, since that would have resulted in a burst tank. Instead, he attached a couple of feet of garden hose to a high point on the tank, and dribbled in water, which pushed out the dent.

Because, you know, hydraulics.

(At least, it blew my mind, man)