Amplifying a gardening thread into a parable:

I once had a garden in Somerville, MA ("the compost heap behind Harvard Yard") that was infested with what we called Japanese Bamboo (or knotweed).

Japenese Bamboo is the most invasive species you can ever imagine--I swear I once turned my back on it, and heard this crackling noise, and turned back to look at it, and it had grown several inches.

So there was a massive stand of this spectacularly invasive stuff growing high overhead, and I tried everything I could think of to get rid of it (except flamethrowers). I started out by chopping it all down, and then pouring the local hardware store's version of Agent Orange all over the roots. That worked for a few hours, until I saw little green bamboo shoots poking up through the soil again. So I went back to work, and systematically ripped all the new shoots up by the roots, went to bed, and didn't get up until the next morning, when--