Leaving your kingside without defenders and moving one of your pawns (or two!) defending the castled position is not a good idea. Kopetzky-Engert, 1941 went: 1.e4 e5 2.Nf3 Nf6 3.Nc3 Bb4 4.Bc4 0–0 5.d3 d5 6.exd5 Nxd5 7.0–0 Nxc3 8.bxc3 Bxc3 9.Rb1 Nc6 10.Ng5 h6 11.Ne4 Bd4 12.Qh5 Na5 13.Bg5 Qe8 (see diagram) and now White wins in all variations. Do you see them all?
The game continued: 14.Nf6+ gxf6 And you don’t even need to win the queen![14...Kh8 15.Bxh6 gxf6 (15...Qc6 16.Bc1#; 15...g6 16.Qh4 Bg4 17.Bg5+ Bh5 18.Nxh5 Qc6 19.Nf6+ Kg7 20.Qh7#) 16.Bg5+ Kg7 17.Qh6+ Kg8 18.Qg6+ Kh8 19.Bxf6#] 15.Qg6+ Kh8 16.Bxf6#