In a world where so much of our communication is delivered through emails, what better way to remind kids of their manners than through the Bun-Burger-Bun theory.
When speaking to someone directly, you don't just dive directly in to what they can do for you. Instead you use manners to check in with that person, greet them, then get to your point. After, you don't just walk away! You finish up your request, thank them, and wish them pleasantries. The same should be true for emails!
This outli