Also how do you quantify a bad trade? How much lost money? I trade on Robinhood too (not GME though), and just two weeks back I lost money on Nio stock. Is tha

Also how do you quantify a bad trade? How much lost money? I trade on Robinhood too (not GME though), and just two weeks back I lost money on Nio stock. Is that a bad trade? Should Robinhood have stopped me from buying that stock?