When you are out on a walk with your dog, do they have little quirks that seem to come out? For one of my dogs, Arya, it was any change in the surface we were walking on, particularly metal. Every time we would come up to a metal grate or manhole cover on the sidewalk, she would make an extra effort to avoid walking over the surface. This is a confidence issue, plain and simple. Further, it indicates a scenario where the dog would rather transition to being defensive, instead of comfortable, where we ideally want them to be.
In order to teach her to be accepting of the surface, I restricted her options every time we were met with a metal surface on our walks. As we would move toward the grate or metal cover, I would shorten the leash and apply gentle pressure to her collar to restrict the directions she could move. I didn't drag or force her. I just calmly and gently confirmed for her that to move forward, her only option was over the grate. At first, just putting one foot on the grate was enough for me to release the tension on the leash and then we'd move around. After a few reps, she was going over these grate hurriedly but completely. On the next walk and with a bit of review, we were able to walk over them calmly. And lastly, we started practicing sit-stays for short periods of time.
Running into a situation like this while you are out with your dog might not seem like a big deal. But these little moments add up. Every time you allow your dog to take the easy route, you are limiting an opportunity to build trust with you and self-confidence in the dog. As with everything else in training, follow through is the number one most important factor in your relationship with your dog. You have to be believable. If surface changes are nothing to worry about, Arya needed to believe me, and that meant showing her that we could walk over them together. It's creating a mild stressor, that the dog can overcome, and continually building on that success until it's no longer a problem.
We do this in our own lives too. We allow ourselves to just side step small things, avoiding a task (however minimal), uncomfortable conversation, etc., until we have a much larger issue. For me, it's diet. I know what I should eat, but don't, even though the amount of effort it would take to make that change is relatively small on a daily basis. I don't even have to cook, just make a better choice.
So if there is that one house with the barking dog in the window that sets your dog on fire, that one bush that always has a bird in it that the dog wants to hunt... Take some extra time to work through those moments. Be careful to go in bite sized chunks, treat genuine effort as success, and not to over pressure your dog. But take the time. A 10 minute walk and 20 minutes working on an issue like this does your dog FAR more good than mindless trucking down the street for a half hour. These moments... they are not problems. They are opportunities to resolve behavior issues, solidify obedience, build trust and self-confidence, and show your dog that you are every bit of the leader, teacher, advocate, and cheerleader that they need in their life. All those little wins add up to better habits and better self-esteem.