1. Mr Bergstrom
Mr Bergstrom appears briefly as a supply school teacher at Springfield Elementary in the classic 1991 episode 'Lisa's Substitute', and almost immediately earns Lisa's affection. Lisa's regular teacher, Mrs Hoover, comes down with a bout of Lyme Disease and Mr Bergstrom takes over the class, with his inspiring - if not unorthodox - teaching methods making him popular with the pupils. Lisa is enamoured by Bergstrom, who helps her discover a new thirst for learning, while he even takes Homer to one side to encourage him to be a better role model to his daughter after he embarrasses her at a museum. Lisa is crushed when she finds Hoover has recovered from her illness and is back teaching, and that Bergstrom has left Springfield for another job. She catches up to him before boarding a train, and tearfully confesses that she will miss him. Bergstrom then comforts Lisa by writing a message on a piece of paper, telling her that if she ever feels alone or can't rely on anybody, its contents will make her feel better. The message simply reads: "You are Lisa Simpson".
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