Deeper tactics and defense
I played the following game as black on live chess (standard time controls) where I quite early on equalized after some opening inaccuracies by white.
After a (decisive) blunder on my opponents side, I started to tear through his position with my bishop pair, which coined me a rather quick win and left me rather content. But when analyzing the position later on (with Fritz 11) it turned out white had missed some important defensive resources. (Needless to say so did I)
None of these defensive resources would have objectively saved the game, but they would have allowed him to carry on longer with better chances of survival. Because of this, I had to admit that some of my 'decisive killing blows' were actually just the start of an undesirable continuation.
The lesson was that if you think you see a good attacking tactic, look deeper. You have to be creative when looking at the possibilities for your defending opponent too!