MISTAKE!

If a BARBER makes a mistake its a
new style,
 
If a POLITICIAN makes a mistake
its a new law,
 
If a SCIENTIST makes a mistake its 
a new invention,
 
If a TAILOR makes a mistake its a
new fashion,
 
If a TEACHER makes a mistake its
a new theory,
 
If a STUDENT makes a mistake its
a "MISTAKE"