Sometimes, access to the top starts with something as simple as a stamp. General Motors CEO Mary Barra has noted that she responds to “every single letter” she receives. Despite leading a nearly $75 billion automaker—and the fact that AI has turned once-tedious tasks such as drafting emails into seconds-long chores—Barra still writes back the old-fashioned way: with pen and paper. The notes she receives range widely, from loyal Chevrolet drivers sharing their car’s nickname to schoolchildren worried ab ...