Dear Douche Twizzle,
My kid, your ex-employee, is 16 nearly 17 and on the cusp of being an adult. Do you know what you call a human who is on the cusp of being an adult? A child.
I would agree that the way my son ended his employment with you was not done in a professional manner. He was unhappy working at your frozen yogurt store. It would have been great for him to give you two weeks notice instead of finishing his shift, then sending you an email that he quit. After all, you give two weeks notice when you terminate employees, right?