If you think education is expensive, try ignorance. (Attributed to both Andy McIntyre and Derek Bok)

You must always, always, always, look on the bright side of things:

If there were no schools to take the children away from home part of the time, the insane asylums would be filled with mothers.  (Edgar W. Howe)

Something else to take into acount: 

The mediocre teacher tells.  The good teacher explains.  The superior teacher demonstrates.  The great teacher inspires.  (William Arthur Ward)

Finally, someone I never tire of quoting:

I am always ready to learn although I do not always like being taught.  (Winston Churchill)