Chess Opening Theory/1. e4/1...e5/2. Nf3/2...d6/3. d4/3...Nd7/4. Bc4/4...Ne7

4...Ne7??
This move cramps Black's position even further and allows Ng5, when f7 cannot be comfortably defended. One example: d5 Qh5 (g6 Qf3 (Nf5 Bxd5) f5 Ne6 wins the queen) Ng6 Bxd5, and Black won't live very long due to f7.