I prefer the version in which a man comes home from work early, glances into the bedroom, and then goes to sharpen his razor.  "Whatever are you doing that for, dear?" his wife asks him.  "Well," he replies, "If those shoes under the bed are my size, I'm going to shave."  One of a number of not-too-subtle versions of old jokes done by Laff-Gram in the 1950s or thereabouts; never mailed or messaged