Tactics are actions that you take in the moment. Some outside event happens, and you react based on that event — for example, you’re driving and another driver beeps his horn at you for seemingly no reason. You give him a one-finger salute.
Another word for tactics is “reaction”. Reactions just lead to more reactions, from you and from the environment you’re reacting to.
A concept — or theme or strategy — is a way of being that governs your response to anything and everything that could possibly happen.
A response is measured and thought-out ahead of time. A reaction is knee-jerk and immediate, impulsive and not thought about until after it happens. A lot of mistakes are made in reaction.
A tactic is to yell back at any driver who dangerously cuts you off in traffic. A concept for handling reckless drivers can be to consider that someone may be in a rush, having a bad day or may have not even seen you before they made their ill-advised lane change. The external event already happened and you can’t change it, so why not adopt a concept that keeps you calm and centered, rather than always reacting to the environment?
A tactic is black and white — if this happens, I do that. But you won’t always be able to do that, which will lead to frustration and more tactical reactions. A concept is not based on the outside world; it’s based on your response to the world, which you control.