How does a problem propagate itself?

And suppose we solve all the problems it presents? What happens? We end up with more problems than we started with. Because that's the way problems propagate their species. A problem left to itself dries up or goes rotten. But fertilize a problem with a solution -- you'll hatch dozens.

N.F. Simpson, English playwright "A Resounding Tinkle" (1958) act 1, sc. 1