Thomas Sowell has an especially good column today. The second sentence should cause us all to pause when we seek to "make a difference:"
"I would be scared to death to 'make a difference' in the way pilots fly airliners or brain surgeons operate. Any difference I might make could be fatal to many people."
Each and every one of our areas of expertise extends over an infinitesimal area of the great totality of knowledge. Better that we stick to and improve our own little corner of the cosmos than step into someone else's corner and screw it up.
Read the whole column. Well worth a five minute investment.