Its a rule from the list of "How to Write Gooder"

• Analogies in writing are like feathers on a snake

• Go around the barn to avoid colloquialisms.
• Propositions are not words to end sentences with.
• Who needs rhetorical questions?
• One word sentences? Eliminate.
• The rest can be found Here though I think the original version of the list was started by Dave Barry.

There is a fine line between hobby and obsession. I seem to have lost sight of it some time ago.