my backtest showed +500% and live trading is negative — here's why 💀

ran my strategy through a backtest, got +500% on historical data, felt like a genius. went live = negative lol. turns out ① overfitting (tuned to the past only) ② ignored fees + slippage ③ accidental future-data peeking (lookahead). a backtest was just a hopium machine... subtract real trading costs and it's a different world