critical mass

n. In physics, the minimum amount of fissionable material required to
sustain a chain reaction. Of a software product, describes a condition of
the software such that fixing one bug introduces one plus epsilon bugs.
(This malady has many causes: creeping featurism , ports to too many
disparate environments, poor initial design, etc.) When software achieves
critical mass, it can never be fixed; it can only be discarded and
rewritten.

