Consistency with your dog
Can you imagine taking your dog to someone else's house and having them behave? It's not about magic, it's not about treats, it's not about getting a "good dog" -- it's about consistency. If you guys bust butt and work daily, teach your dog, give direction and fair reward and consequence, and apply it at home, outside, and up the distractions on a daily basis you CAN have a dog who can be an excellent canine citizen in the real world.
Have you ever wondered why a Service Dog is so well behaved? It's because this dog has been proofed by their handler often for years and now have a dog who's predictable and dependable in the world. Put in the work and you can have great turnover! Down/stay at home, on the sidewalk, at a restaurant, or at a friend's -- proof your dog and focus more on direction than affection for a while, and enjoy your dog all of the time :)