Related:

• What matters today is not the difference between those who believe and those who do not believe, but the difference between those who care and those who don't.
  -- Abbe' Pire...
• Those who run are enemy. Those who don't are well trained enemy.
• Those who can, do. Those who can't, teach. Those who can't teach, administrate.
  Those who can't administrate, consult. Those who can't consult, run for political office....
• The world is run by those who show up.
• Those who can, do. Those can't, teach. Those who destroy everything they touch, become high school counselors.
• I don't know what your destiny will be, but one thing I do know
  the only ones among you who will be really happy are those who have sought and found how to serve....
• Those who can, do. Those that can't criticize.
• H. L. Mencken's Law Those who can -- do. Those who cannot -- teach.
  Those who cannot teach -- administrate. (Martin's extension)...
• This isn't true in practice -- what we've missed out is Stradivarius's constant.
  And then the aside: "For those of you who don't know, that's been called by others the fiddle factor....