An old boss of mine had a great system for managing her email. It is called the “trash”.

Whenever you finally got to the point were you desperately needed for her to respond to an email you had sent her, you would go to her office and say, “I need an answer on the email I sent you about X.” “What?” she would say, “I never got that.” Then you would have to say, “Really? Are you sure? Check your trash.” She would, and after only five or ten minutes of narrowing down the date, etc, to find it, she would read it and give you your answer.

Ah. Good times.