Getting Rid of the Mitzri in Us

After ten plagues, Hashem says the Egyptians will "know that I am Hashem" only when the sea splits. What did they not know until then? And what did Pharaoh mean by "Who is Hashem?" The Ramban's distinction between Hashem's names answers both, and explains why the redemption came in two stages. It also asks how much of Mitzrayim we still carry with us. A man who lost everything in someone else's failed investment puts the idea into a real life.