You cannot teach a crab to walk

Related:

• You cannot teach a crab to walk
  straight. --...
• You cannot teach an old dog new
  tricks...
• The ill-tempered cannot
  teach. --...
• Even if you persuade me,
  you won't persuade me. --...
• You cannot teach a man anything.
  You can only help him to find it within himself. ...
• You cannot teach a man anything.; you can only help him to find it for himself.
  Galileo...
• Jerry, You are just like a crab, always on the ball.
  <G<...
• He who ceases to learn cannot adequately
  teach...
• Quote #675 You cannot teach beginners top-down programming,
  because they don't know which end is up. --...