The single most useful habit you can build with a nervous dog is to pay attention not just to whether you are using treats, but to how and where you actually deliver them, because food that a frightened dog has to overcome its fear to reach can quietly stop being a reward and start becoming a warning. Food is the thing most of us reach for first, and for good reason, because there is plenty of it, we can keep it in a pouch, and dogs tend to love it, which makes it the simplest way we have to reinforce a behaviour we would like to see again. There is an important difference, though, between reinforcing a behaviour that has already happened and dangling food in front of a dog to coax it towards something it finds frightening, and it is that second situation where good intentions can quietly backfire.
Picture the familiar scenes, a little pile of treats placed on the vet's weighing scales in the hope the dog will wander over, or a stranger holding out food and waiting for a wary dog to close the gap and take it from their hand. In theory it seems to work, because the dog does the difficult thing and gets the reward, and we assume the good feeling of the food will carry the day. If the thing in the middle is genuinely scary, however, you are no longer offering a simple reward, you are placing the dog into conflict, because now it desperately wants the food and it desperately does not want to approach the thing, and it has to choose between the two. Conflict like that feels awful, as any of us knows from wanting something and dreading it in the same breath, and either way the food stops being a happy, tail-wagging positive and becomes tangled up with apprehension.
Repeat that often enough and the dog can begin to read the appearance of a treat itself as a prediction, so that food coming out of the pouch starts to mean something unpleasant is about to happen, whether that is being touched, handled, or nudged towards a place it would rather avoid. Once that association forms, the treat meant to say you are safe ends up saying brace yourself, and the dog may turn down food it would normally love, not because it is not hungry but because it has learned what tends to follow.
The fix is small and it changes everything, because instead of asking the dog to close the distance for its food, you have the treats thrown so they land in the space where the dog already feels safe, and the reward arrives with no demand attached to it. The message then becomes that good things turn up right here, where you are comfortable, and you do not have to push through anything frightening to earn them, and the person who gently tosses treats into a nervous dog's safe zone every time they are near soon becomes the human who makes good things happen. From that steadier place, in its own time, the dog will often choose to come a little closer, and then closer still, which is exactly what we were hoping for all along.
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