We all have the experience of immediately seeing what is wrong with a move AFTER playing it. From a more scientific standpoint, why do you think we have this blind spot?
I think the most common situation is that we are looking at one problem, and become fixated on solving that problem, and we find a move that solves the problem. Then, and only then, do we ask, "Now, are there any other problems?"
I find that I make this kind of error most often when I slip into the perception that I already have the game won, or that I already have a comprehensive understanding of the position. It's that smug sense of relaxation, the idea that the position holds no more secrets for me, that's the sorrce of most of my blunders. Consequently, I've come to think that a lot of blunders can be attributed to a kind of hubris -- to losing one's sense of humility before the complexities of the game -- when the reality is that even seemingly bare endgames often contain potential shocks and surprises. This best corrective I've found is twofold: To acknowledge that most positions actually comtain more secrets than they seem to at first, and to "sit on your hands" before moving (which is, of course, easier said than done).