Share 'Informality of Email'

Lately, many of the emails I am receiving from students lack any formality. It is driving me crazy! I don't like being addressed as "Hey" in person... and I don't like being addressed as "Hey," in an email. My sister, who works on Wall Street, had to sit down with her college interns this summer and give them a lesson in how to use email appropriately in a business environment. Have any of you su…