It's easier to combine separate red, blue, and yellow playdoh blobs into one big grey blob than it is to separate a grey blob of playdoh into red, blue, and yellow blobs.

''Also known as the SecondLawOfThermodynamics.''

This is a metaphor for avoiding coupling in software.  It's always easier to combine small, self-contained code or data than it is to decouple code or to parse data.

See also: PrematureConcatenation, WhatIsEntropy