You've taught your dog basic obedience commands. He can sit, lie down, stay and come when called. He walks quietly on a leash. But as soon as someone comes to visit or you try to take a walk in the park, he suddenly acts as though he never heard these commands before.
Never fear. Your dog is trained, but there is still more work to do. He hasn't learned that he has to obey in new places and around new people and dogs. It takes just a bit more practice but you can soon have a dog who listens to you no matter what is going on around him.