I Think the “Evil Birth Mother” Trope in Secret Identity Stories Is...

That's a fair point. A doctor occupied the original owner's body for two years. She was bad at school and everything else, dropped out to join the entertainment industry, and even lip-synced. If I were her mom, I'd be furious. Then the original female lead comes back and the impostor gets exposed and goes crazy. It's pretty satisfying if you turn your brain off.