Never follow your first reaction—it is what the opposition expects
This gem came from the director of an intelligence service of a small European country.
Chances are, rival spymasters are almost as smart as you. They certainly didn’t get their jobs by being stupid.
When your adversary does something, and you are expected to react, think long and hard about why they did what they did it, and what they anticipate you are going to do about it.
They are probably chess-players, looking three moves ahead.
Do not fall into their trap by making the move they expect of you.