The Shimada brothers arrive at your door. They knock and wait for you to answer. When you open the door, they politely ask to come in with a bow. They know it pleases you to pull this cultural stuff of theirs on you, even if you don’t know much about it. You let them in, and they try to enter at the same time, bumping shoulders.
When they shoot each other a charged look, you know there might be trouble.