Lisa's Substitute

At the train station, Lisa catches Mr. Bergstrom as he's about to board the train to Capital City. Lisa begs him not to leave.

That's the problem with being middle-class. Anybody who really cares will abandon you for those who need it more. -- Mr. Bergstrom's parting remarks, "Lisa's Substitute''

Lisa tearfully understands. He tells her, "Whenever you feel that you're alone and there's nobody you can rely on, this is all you need to know,'' and hands her a note. Lisa chases the train as it pulls away, then looks at the note. It reads, ``You are Lisa Simpson.''

-The Simpsons