11. Goodbye, Martha

(“The Magic of David Copperfield V: The Statue of Liberty Disappears,” season 4, episode 8)

In another heartbreaking ending for a wonderful supporting character, Martha finds out that Philip is actually a Russian spy and in order to keep herself safe, agrees to flee the U.S. for Russia. It really boils down to how much she loves him, even insisting during their goodbyes that he try not to be alone and lonely.