We can learn much from wise words, little from wisecracks, and less from wise guys. — William Arthur Ward. American writer and academic (1921–1994)
It is wise to direct your anger towards problems -- not people; to focus your energies on answers -- not excuses.
The mediocre teacher tells. The good teacher explains. The superior teacher demonstrates. The great teacher inspires.
The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.