Related:

• Never try to teach a pig to sing. It wastes your time and annoys the pig.
• Never try to teach a pig to sing. It's a waste of your time and annoys the pig. -- Anon.
• You shouldn't try to teach a pig to sing. You waste your time and it annoys the pig.
• The moral is: Never try to teach your parents anything.
• This tag wastes your time and mine...
• A pig is a jolly companion, Boar, sow, barrow, or gilt -- A pig is a pal, who'll boost your morale, Though mountains may topple and tilt.
  When they've blackballed, bamboozled, and burned you, When they've turned on you, Tory and Whig, Though you may be thrown over by Tabby and Rover, You'll never go wrong with a pig, a pig, You'll never go wrong with a pig!...