In chess, you do not usually get the kind of "obvious" chess tactics that you find in chess books. The blunders are quite often more subtle. Here is a perfect example.
In this chess position, it is white to move.
1.f4 Nc6 2.Rxd5 Rxd5 3.Rxd5 Qf8 4.Qd3 Qb8 5.Rd6 Rc8 6.Nd2 Rd8 7.Rxd8+ Qxd8 8.Qxd8+ Nxd8 9.Nc4 Nc6
it's a winning position for white