Never date the Invisible Man
on any given night
you will never be able to see him
and won’t know if he is there.
If anyone sees you talking to yourself,
they might send for the men in white coats
to come and take you away.

Never date the Bionic Man
or you will never know
if he will put a big squeeze on you
and break a bone or two.

David Harris

http://www.poemhunter.com/poem/another-few-things-you-should-never-do/